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Demon Internet Ltd.
==================
Gateway House
322 Regents Park Road
Finchley, London, N3 2QQ
0181-371 1234 (Sales - London)
0131-552 0344 (Sales - Edinburgh)
0181-371 1010 (Help Line)
0181-371 1150 (Fax)
0181-371 1000 (Switchboard)
email internet@demon.net
MODEM.TXT - INFORMATION ON CONFIGURING A MODEM FOR CONNECTING TO THE
INTERNET
Last updated: 21 July 1995
The latest version of this document is available from
ftp.demon.co.uk:/pub/doc/Modem.txt
_________________________________________________________________
Contents
1. General
2. Essentials
3. Telephone Exchange
4. Internal Modems
5. Which Phone Number
6. Modem and Telephone Leads
7. Serial Chips
8. Speed
9. Trouble Shooting
10. Software and Other Factors
11. Help for Specific Computers
[ IBM PC Compatibles running DOS | OS/2 | Windows NT | Macintosh ]
12. Individual Modem Settings
1. Setting up a kind of modem not described below
2. Setting Up a US Robotics/Miracom Modem
[ Courier 14.4 | Courier V.34 | Sportster 14,400 | Sportster
28,800 ]
3. Andest
4. Apple Express Modem
5. BT NS 2232 M
6. Dowty
7. Dynalink
8. Gateway
9. Harmony
10. Hayes modems
11. Mistral
12. Multitech
13. Nokia
14. Racal
15. Rockwell chipset modems:
[ DFI passport | Pace Microlin | Pace Mobifax | Global
Village | Reveal | SmartOne | Supra | Zoom ]
16. Tricom
17. Yoriko modems
18. Zoltrix
19. Zyxel
13. Testing
14. Finally
_________________________________________________________________
1. GENERAL
This document will point out some general essentials and advice on
setting up your modem. A section at the end discusses specifics
regarding a DOS setup running the KA9Q NET.EXE program. Due to the
vast combinations of computer and modem setups it is impossible to
give specific help for all types.
Making an Internet (IP - Internet Protocol) connection via a modem is
very different from a standard dial-up connection. Do not assume that
just because you can download from a BBS (and maybe upload) or use
other services that you have your communication (comms) set-up 100%
sorted out. Due to the nature of IP, if you get errors, throughput can
be hit very badly. Under IP information is sent in packets and for
maximum speed these should generally be as large as possible up to a
maximum of about 1500 characters. If a packet gets messed up (garbled)
its entire contents will have to be resent - hence a large speed
degradation may occur.
One exception to this is when an interactive sessions are sharing a
TCP/IP link with more voluminous transfers such as NNTP or SMTP. In
this case it can be preferable to have smaller transmission units
(Maximum Transmission Units setting or MTU) so that keystrokes/screen
updates will fit into the data stream with less delay. If a large MTU
is used this can lead to what feels like a jerky or intermittent
session.
Enough of the technical parts, there follows some sound advice that
everybody should take note of.
_________________________________________________________________
2. ESSENTIALS
Correct modem settings:
* Full hardware handshaking (CTS/RTS),
* Flow control
* XON/XOFF (software handshaking) set to off
* Settings must be bi-directional where appropriate.
* A full specification modem cable (open yours up - if it has only 3
wires it is no good).
* A serial port chip that can cope with the high speeds (if using a
high speed modem). Extended memory drivers and Terminate Stay
Residents (TSRs) etc. can interfere with the handling of
interrupts from serial chips.
_________________________________________________________________
3. TELEPHONE EXCHANGE
The Demon Internet Service (DIS) is on modern digital exchanges so you
should have little trouble with ringing tones etc. when connecting to
us. If you are on an older exchange, your modem may not recognise the
dialing tone. If this happens, look in your manual and change the
setting that overrides the dial tone recognition.
Note that when you make changes to a modem's settings you should
always reset the modem first, make the change and then save the
settings. You will need a comms or "terminal emulation" package such
as Telix, Procomm, Window's Terminal, Z-Term, Microphone etc. Look in
your modem manual for instructions. Mostly you will be able to type
ATZ <return> to reset your modem. On a US Robotics/Miracom modem you
could type:
ATZ Reset the modem
ATX3 Alter a setting
AT&W Write the settings to Non-Volatile RAM (NVRAM)
The last bit (AT&W) is useful as it means that when the modem is
reset, it will remember the settings you have stored.
If going through a private telephone network (or PABX) first, you will
probably need to dial a number such as 9 to get an outside line. Make
sure your dial string has this in. You may need to separate this from
the number to dial by a separator such as a comma so that there is a
pause to give your telephone system time to give you an outside line:
9,01813434848
Make sure that if you're attaching your modem to a PABX line that the
line is attached to a standard analogue line card on the switch, and
not a specialist 4-wire (as seen on many SDX phone systems), ISDN or
ISDT lines.
Make sure that you don't have call waiting enabled on your phone line.
The usual little beep you would hear on a line isn't too intrusive on
a voice call, but causes havoc with modem signals. If you are unsure
how to disable call waiting, contact your phone company. (It's
normally #43# on BT digital exchanges)
_________________________________________________________________
4. INTERNAL MODEMS
Internal modems have the advantage of not having a serial lead to
worry about, and have matched serial port chips built in, but the
disadvantage of using an extra interrupt and generally don't have any
lights to let you know what is going on. Ensure that the interrupt on
which the modem sits does not interfere with any others - refer to the
setup program for your computer and your modem manual. This may
require altering a jumper (a small connector) on the main computer
board (mother board) on your computer or on a separate board. This
should be well documented and is well within the scope of the average
user. Ensure that the modem is seated correctly in the expansion slot.
_________________________________________________________________
5. WHICH PHONE NUMBER
We have multiple Points of Presence (PoPs) - please see
/pub/doc/Demon.txt for details. Thus you will have a choice of
numbers to ring. You may use any of our PoPs at any time.
_________________________________________________________________
6. MODEM AND TELEPHONE LEADS
Your modem lead should be in good condition and preferably not wrapped
in a tight circle or running parallel to high power cables etc. This
will normally only affect longer runs and, as your cable should be
earthed, will not often be a problem. The cable should be connected
securely at both ends as should the telephone cable. If you suspect
your telephone socket may be causing a problem then test it with a
standard plug in telephone. Use the correct type of modem lead - they
vary from country to country. Although two modem to phone socket
cables may look identical, they are often electrically different -
some are straight-through cables, and some cross the cables over, the
end result can mean the "NO DIALTONE" message from your modem. If you
have more than one modem, don't switch cables between them.
_________________________________________________________________
7. SERIAL CHIPS
The type of serial chip (Universal Asynchronous Receiver/Transmitter -
UART) in use can make a big difference to comms
performance/reliability. At higher speed the computer can sometimes
not service the serial chip fast enough to catch all of the characters
arriving down the line. This problem increases if running under a
multi-tasker such as Windows, certain memory managers and other TSRs.
_________________________________________________________________
8. SPEED
Close to every modem user's heart is the speed at which they can
operate. There are two different speeds: the first is the speed at
which a modem can talk to another modem; the second is the speed at
which the modem can talk to its controlling computer (the DTE rate).
Firstly, we will discuss the connect rate. A V.22bis modem can connect
at a speed of 2,400 bits per second. There are 8 bits in a byte (a
byte is usually one character) so that is a maximum of 300 characters
per second (cps). Due to start and stop bits, each byte will take 10
bits reducing the speed to 240 characters per second. When running
over IP there is a slight overhead and so you will never see this
maximum. However, as you can (and will) have several things happening
at once, you will be able to make very good use of your available
bandwidth.
The fastest connect rate currently possible is 28,800 bits per second
(V34). For modems to negotiate at this speed requires a good quality
phone line, and a modem at each end that is capable of the V34
protocols. Demon are in the process of upgrading all its modems to V34
capable modems.
Many modems have compression protocols built in to them. MNP/4 and V42
use synchronous connections to provide an error free connection
between modems, saving the start and stop bits. This gives at least a
20% increase in throughput. V42bis adds compression, provided that the
DTE rate is higher than the connection rate. This means that when
downloading a plain text (or ASCII) file, it is possible to get faster
speeds by compressing the data. The data is compressed so that the
same information can be encoded in to a smaller space. The receiving
modem will of course unscramble the data for you. If news normally
flows in at say 200 cps, then, on a 2400 cps link, you have up to 44
cps left at the same time for mail, telnet'ing, ftp'ing etc.
Compression techniques do not work as effectively on binary files and
make very little difference to pre compressed files (such as .zip,
.zoo, .lha, .gif etc.).
Note that MNP5 will usually degrade throughput on an IP link due to
the packet based nature of it's compression method. V42bis does not
suffer this problem as it is capable of optimising itself dependent on
the type of data being transferred.
Now we will discuss the second speed - the speed at which the modem
and computer communicate with each other. This is called the Data
Terminal Equipment (DTE) rate. If you have a slow modem, e.g. a 2400
baud one without MNP or V42, then it will probably only work correctly
when talked to by the computer at the same speed. For the facts on
your particular modem and computer you should refer to your manuals.
On faster modems you will only be able to take advantage of some of
the compression features by making the computer talk to the modem at a
faster speed than modem is talking to the remote modem down the
telephone line. Thus you should talk to a 9600 modem at 19200 or even
38400. You should check the maximum speed at which the serial port on
your modem can talk and then set your communication package to work at
the highest mutually available speed. Don't forget that without a
buffered UART you are unlikely to sustain reliable high speed comms
above 9600 baud. Modems normally will not negotiate modem to modem
connect speed higher than the DTE rate - You won't get maximum
throughput on a fast modem if the computer cannot communicate
efficiently at a high speed.
Please note that we only support modems capable of V22bis (2400) and
upwards. If you have a US Robotics/Miracom HST modem, you may not get
very good throughput in HST mode. In practice HST mode is fine if
FTP'ing from a site without anything else happening (sending mail
etc.) as it works fine in one direction at a time only.
9. TROUBLE SHOOTING
If you are getting garbled characters on the screen then something is
wrong! Garbled characters are often a sign of mismatched speeds, lack
of handshaking or a non-locked DTE rate. If you get as far as the
login prompt but no further then make sure that your dialer script is
working on 8 bit standard comms: 8 bits, no parity, 1 stop bit. See
/pub/doc/Demon.txt for the full logon script details.
Having checked your setup according to the information above, try
reducing the speed at which the computer talks to the modem (if using
a high speed modem) until the connection works. If you have to do this
then either you are attempting to drive your computer or your modem at
too high a speed, or you have other processes running which interfere
with the correct running of your serial communications (as per Serial
Chips above).
If you have finished your live session and log off you may sometimes
find that your phone line is not dropped. This can result in an
unwelcome phone bill! There are a number of computer/software specific
solutions to this problem and some answers are given in
/pub/doc/Support.faq which may have been included in your
installation. One thing to check on your modem is that the setting
that makes the phone line drop when the computer tells the modem that
it has finished, is on. The computer uses the serial port and drops
DTR (Data Terminal Ready) and the modem spots this and hangs up the
line. The setting often &D2 and you should read the section below
which tells you how to set this. It is definitely &D2 for US Robotics,
SupraFax and Dowty Quattro modems.
If your modem sometimes seems to fail to recognise a ringing tone,
reporting it as BUSY. This can be cured by adding a comma after the
dial number, e.g. "ATDT0813434848,". This makes the modem pause and
ignore the first rings which it sometimes things is a busy single.
Some US Robotics modems can exhibit this problem.
ATZ is the command that resets the modem. Setting your initialisation
string to ATZA0 etc. where A0 is the initialisation string is very
likely to fail. This is because the modem takes a while to reset and
throws away the data being sent to it in the meantime. Some people beg
to differ on this point. However it is certainly true on US Robotics
modems.
Just to confuse matters further there are often some switches on the
modem which you can use to make further settings or to default to
different options. These are referred to as DIP switches. Mostly, the
advice contained in this document, refers to modems that have not had
their switches tampered with. If you have the manual for your modem
(and I hope you have!) then that will probably tell you what the
default factory switch settings were. Make a careful note of the
current settings and then change back to the factory defaults. If you
already use your modem with other packages, make sure they still work.
These DIP switches must be set to ensure that the reset command ATZ
resets the modem to the stored values. On some modems it is possible
to make ATZ restore to factory settings which rather defeats the
object of configuring it! Some modems have ATY commands instead of DIP
switches and so it is important that the correct ATY command has been
used. Fortunately, the default will be OK if no ATY command has been
issued.
If you are getting a no response from the modem before dialing (e.g.
The dialer in KA9Q reporting "INPUT LINE WAIT 3000 OK") then that
means that either your modem is not connected properly (check the
cables, or for internal modems, check jumper settings, and check
software configuration to check that the dialer is trying to talk to
the modem on the correct port), or your modem is not configured for
verbal result codes. Normally the command to accomplish this is ATV1 .
If the modem starts negotiating and starts whistling (especially with
a 2400 connection)
dial vPoP with &G2 (UK guard tone)
Modem drops line after 1 second
Modem could be set for non-full duplex
There is a section below which specifically refers to problems that
may be encountered by PC users.
_________________________________________________________________
10. SOFTWARE AND OTHER FACTORS
By configuring your software correctly you can make significant
improvements to an under performing communications connection. Things
to check for include badly fragmented disks (run a disk de-fragmenter
such as Norton's Speed Disk), no disk cache, no or insufficient
buffering inside the software and unnecessary checking protocols or
indexing taking place. Refer to your software's instructions for
details on these.
_________________________________________________________________
11. HELP FOR SPECIFIC COMPUTERS
Some extra comments for some operating systems which may be of use
follows.
IBM PC Compatibles running DOS
In addition to the above information there is some specific advice
below for those of you running DOS.
Some modems send back "OK" when sent ATZ (the reset command) even
though they are not ready. This means that the dialer program will try
to ring out even though the modem is not ready. The effect is that you
will see ATZ on the screen followed by OK and then the program will
not dial. Eventually it will time out. To avoid this, send AT instead
of ATZ in the modem initialisation string.
Extended memory drivers can interfere with the correct operation of
your serial communications. If you suspect this, rename your
CONFIG.SYS and AUTOEXEC.BAT files and then reboot your computer to see
if the connection improves.
If you have a V.32bis 14,400 modem you will probably want to talk to
it at 38,400. Unless you have a suitable serial chip then you will get
errors and, as explained at the start of this document, this can
seriously impact the throughput. When running NET.EXE you can type
asystat at the net> prompt and information about your serial comms
will be printed to the screen. The interesting parameter is the third
one on the second line, 'hw over'. This shows how many hardware
overruns (characters lost because they weren't fetched from the serial
chip in time) have occurred. These overruns are usually due to lack of
either a buffered UART or hardware handshaking.
As already stated, for maximum performance you will need to have a
buffered chip. For this you will need a 16550A - this is the number
that is written on the chip. The asystat command at the net prompt
will tell you if a 16550 is detected. Unfortunately, even top
manufacturers overlook this area so it is quite likely that your chip
is below par.
If in doubt, open up your computer and locate the serial chip. If it
is not a 16550 then it might need replacing. If you are handy with a
soldering iron you could replace it, but this is not advisable unless
you are really confident. If the chip is socketed then it can be
removed and a 16550 (costing about GBP 16 - we sell them) be put in its
place. If not then you could buy an extra serial card with a 16550
already on it costing from around GBP 30 to GBP 70 depending on the
specification.
Some internal modems use a 16450 with a large buffer (1K) and this may
be enough to stop hardware overruns.
If you are using a standard serial port then the settings offered for
COM1, 2, 3 or 4 in the configuration program in DIS.EXE will probably
be fine. Otherwise you should refer to your manuals and enter the
appropriate IRQ number and I/O base address.
If you install an extra serial card then be aware that if you have,
for example, a mouse on COM1 then you should not use COM3 for your
modem using the default IRQ setting as they share the same interrupt.
There is another factor that can impede throughput and that is
software overruns. Using the NET.EXE software, at the net> prompt
having just received some news or ftp'd a file, type asystat and look
at the figure before sw over. If this is not 0 then you are getting
software overruns. To fix this, increase the buffer size in the attach
line near the top of autoexec.net:
attach asy 0x3f8 4 ppp sl0 4096 1500 38400
Alter the 4096 in the above to be 8192, 12288 or higher until the
software overruns are cured.
More information on tuning is available in /pub/doc/ka9q/Tuning.faq.
Windows 3.1 / 3.11
Windows 3.1 has got drivers that support the 16550A buffered serial
port, however, some software (Delrina WinFAX) installations, for no
particular reason, disable the buffering on it If you have a buffered
serial port, check that in your system.ini file that in the [386Enh]
section, COMxFIFO=1, where x is the number of your serial port with
the modem.
OS/2
If intending to run the DIS DOS software in an OS/2 2.x DOS session
you should get a copy of sio126c.exe and install the communications
driver in it before running DIS. sio126c.zip is available on our ftp
server or via our guest download account. This is because the standard
communications drivers do not pass to DOS the buffering of your 16550A
buffered serial chip.
Windows NT
Windows NT's Remote Access Service (in Windows NT versions 3.5 and
above) has built-in support for a wide range of modems, if your modem
is on the list of supported models, you should select that model. If
it doesn't appear to be supported, you should refer to the windows NT
help file rasphone.hlp, which should be somewhere on your hard disk.
If you cannot get any joy yourself, contact either your modem
manufacturer or Microsoft for an updated modem.inf file that includes
your specific modem.
Macintosh
Be aware that many modem cables sold for the Macintosh do not support
full RTS/CTS hardware flow control.
Many modems do not respond properly if the Macintosh to modem serial
rate is set to 14400, if you encounter this, try setting the port
speed to 19200.
Fax extensions that are loaded in the systems extensions folder will
lock the modem port such that MacPPP cannot access the port; if you
find ConfigPPP waiting for "OK" then try disabling any fax extensions.
12. INDIVIDUAL MODEM SETTINGS
12.1 Setting up a kind of modem not described below
To change the settings of your modem, use a program that can talk
directly to the modem, such as a standard communications package.
(*) In Windows, you can use Terminal (in the Accessories Group),
setting it for the correct connector (COM Port).
(*) On the Macintosh, you can use ConfigPPP by switching Terminal
Window on, and clicking Open. When you are finished, switch off
Terminal Window again. Note that you will not see a text cursor in the
terminal window.
Type the reset command, usually ATZ <RETURN>, and see the response OK.
Then continue through the list of settings. You can type ATI4 <RETURN>
or AT&V <RETURN> to see what your current settings are on a lot of
modems. For connecting to Demon we recommend the following:
* Use V.32bis modulation/CCITT protocols rather than HST
* Originator mode (i.e. Your modem makes the call)
* Local echo ON
* Duplex OFF; receiving system sends duplicate data
* All result codes displayed
* Display result codes in verbal (not numerical) mode, e.g. OK not 0
* Enable additional error control indicator, e.g. LAPM/V42BIS
* Serial port remains at fixed setting
* Modem send CD (Carrier Detect) on connection
* Terminal sends DTR (Data Terminal Ready)
* Data Set Ready (DSR) controlled by the computer
* Hardware CTS (Clear to Send) transmit data flow control
* Received Data hardware (RTS) flow controlled by computer
* Received Data software flow control disabled (make sure the modem
uses hardware flow control, and switch off XON/XOFF flow control,
also known as software flow control)
* MNP 5 data compression disabled
* Variable link speed negotiation
* 1800Hz UK guard tone on. (Probably AT&G2)
When done, type the command that saves the settings to Non Volatile
Ram (NVRAM) (usually AT&W) so that they are remembered when the modem
is reset.
12.2 Setting Up a US Robotics/Miracom Modem
To set up your modem, use a standard communications package. Type ATZ
<RETURN> and see the response OK. Then continue to make the settings.
You can type ATI4 <RETURN> and ati5 to see what your current settings
are.
If you are using a US Robotics modem other than one listed below, try
the configuration for the Courier, issuing the commands one at a time
to find out which ones are accepted.
e.g. type AT&K3 <RETURN>. When done type AT&W <RETURN> to save the
settings to Non Volatile Ram (NVRAM) so that they are remembered when
the modem is reset.
Some US Robotics occasionally mistake a System X (and Y?) ringing tone
for a busy tone and hang up just as the Demon end answers. Sticking a
pause on the end of the dialing sequence stops the modem's response
long enough for the Demon end to start its negotiating sequence. This
means that the confusing System X tone is ignored. If the Demon end is
busy you just to wait a bit longer for the BUSY string, but not as
long as the setting in S7. Add a pause by adding a comma to the end of
the string.
If after trying out these settings you still encounter problems, note
that some USR v34 modems have problems when connecting to some V.FC
modems and random dropping of carriers. USR has issued a new flash ROM
for Couriers (dated 12/02/94) and is making a new ROM chip for the
Sportsers (availability date unknown). Contact USR for details.
Courier 14.4
B0 V.32bis modulation rather than HST
C1 Transmitter enabled
E1 Local echo ON
F1 Duplex OFF receiving system sends duplicate data
Q0 Result codes displayed
V1 Display result codes in verbal (not numerical) mode
&A3 Enable additional error control indicator
&B1 Serial port remains at fixed setting
&C1 Modem send CD (Carrier Detect) on connection
&D2 Terminal sends DTR (Data Terminal Ready)
&G2 1800Hz Guard Tone
&H1 Hardware CTS (Clear to Send) transmit data flow control
&I0 Received Data software flow control disabled
&K3 MNP 5 data compression disabled
&N0 Variable link speed negotiation
&R2 Received Data h/ware (RTS) flow controlled by computer
&S1 Data Set Ready (DSR) controlled by the modem
Courier V.34
As above. The Courier V.34 is capable of training with the vPoP modems
at 21,600 if the DTE speed is set high enough.
Sportster 14,400
B0 V.32bis modulation rather than HST
E1 Local echo ON
F1 Duplex OFF receiving system sends duplicate data
Q0 Result codes displayed
V1 Display result codes in verbal (not numerical) mode
&A3 Enable additional error control indicator
&B1 Serial port remains at fixed setting
&C1 Modem send CD (Carrier Detect) on connection
&D2 Terminal sends DTR (Data Terminal Ready)
&G2 1800Hz Guard Tone
&H1 Hardware CTS (Clear to Send) transmit data flow control
&I0 Received Data software flow control disabled
&K3 MNP 5 data compression disabled
&N0 Variable link speed negotiation
&R2 Received Data h/ware (RTS) flow controlled by computer
&S1 Data Set Ready (DSR) controlled by the modem
Sportster 28,800
As above. If after setting the above configuration, your modem is
having continual problems training, (ends up with a continuous high
pitch screech) then you may have a faulty modem. Contact USR.
12.3 Andest
Andest Rocket
From a customer:
Thanks for the assistance. The string I've settled on for now is:-
ATE1 $F4 &C0 &S0
E1 ECHO ON
$F4 RTS/CTS ON
&C0 DCD ON
&S0 DSR ON
12.4 Apple Express Modem
Just AT&F then AT&C0 to disable compression
12.5 BT NS 2232 M
(Note this doesn't work reliably with dial, but does work with TIP or
with an outboard Kermit script.)
AT &F0 S0=0 X7 M2 &U1 &K0 B0 S30=26 &E5 &R1 &D2 &C1 L3
&F0 reset to factory default
S0=0 suppress auto answer
X7 maximum message generation (for diagnostic purposes)
M2 speaker always on, so you can hear retrains
&U1 RTS flow control
&K0 CTS flow control
B0 CCITT mode
S30=26 CTS follows DCD **, plus defaults
&E5 V.42bis (and LAPM)
&R1 RTS locked on (??)
&D2 DTR is Data Terminal Ready
&C1 CD Normal
L3 Speaker loud
** the theory is that it would otherwise try to track RTS when that is
used for flow control.
12.6 Dowty
Dowty Quantum 144
To configure this modem for CTS/RTS only (hardware handshaking):
&K2 Use CTS on transmission
&U2 USE RTS on receive
12.7 Dynalink
Dynalink 1414VE: AT&Q9W1S37=11S48=0M0
&Q9 The modem will attempt V.42bis, fallback to V.42(LAP-M), then fallback t
o normal mode
W1 Reports the error correction protocol and the carrier speed used.
S37=11 Sets DCE speed (modem to modem) to 14400bps.
S48=0 Disables protocol negotiation. Forces LAPM.
M0 Turns off the speaker. (This thing is loud!).
ATZ or AT&F as the first command as both of these seem to annoy the
modem into false starts.
ACTIVE PROFILE:
B1 E1 L0 M0 N1 Q0 T V1 W0 X4 Y0 &C1 &D1 &G0 &J0 &K3 &Q9 &R0 &S1 &T4 &X0 &Y0
S00:000 S01:000 S02:043 S03:013 S04:010 S05:008 S06:002 S07:050 S08:002
S09:006 S10:014 S11:095 S12:050 S18:000 S25:005 S26:001 S36:007 S37:011
S38:020 S44:003 S46:138 S48:000 S49:008 S50:255
12.8 Gateway
Gateway Telepath modem:
AT&K3 S48=0 S46=138 S36=1
The modem works fine at 38400 and most of the time is OK with 14400
carrier. On occasion it works better by setting it down to 9600 with
n0s37=9 added to the init string.
Gateway Telepath II 14400 Internal modems are actually USRobotics
Sportster 14.4 internal modems.
12.9 Harmony
From a user, unchecked, an initialisation string for a Harmony 28.8
AT&F X4 &C1 &D2 &E1
12.10 Hayes / Boca modems
Note: The term "Hayes compatible" has been completely overused. It
originally meant the Hayes Smartmodem, launched in the early 80's,
which was the first to offer an "AT" command set. Since the
introduction of higher speeds than 1200 baud, compression and error
correction, extra commands have been needed in the command sets of
modems, and almost every modem manufacturer has taken to implementing
them slightly differently.
Boca have recently taken over Hayes and now use the Hayes brand name
on both the existing Hayes modems and on Boca modems.
This section is specifically for the Hayes Accura 28.8 VFast modem.
AT&K1&Q5&W&K1 Enable RTS/CTS flow control
&Q5 Enable error control mode (V42LAP-M)
&W Saves the settings
Note: this configuration is apparently not foolproof.
Hayes Optima 28.8
(From Hayes themselves)
AT&F &C1 &D2
&F Factory settings
&C1 Carrier detect line in normal use.
&D2 DTR dropped by computer drops the connection
12.11 Mistral
For an Amber Logic Mistral FX144 modem.
Use the factory defaults and the following:
&E4 Forces the modem to reject the connection with the
'NO CARRIER' message if it cannot establish a V42 link
S31=2 Locks the DTE baud rate to 38400
12.12 Multitech
AT&F
This just resets to factory settings.
From one of our users with a Multitech MT1932ZDXK V.32Ter and fax
modem:
AT&F &E2 &E7 $MB14400 X4 M0 S0=0
The X4 just gives you full result codes - not essential unless you
want to know exactly what kind of connection you've got.
From a Multitech dealer:
&E4 Hard CTS/RTS
&BA0 Baud rate altering off
&E2 V.42 with no fall back to MNP5
&E15 Compression on
&D2 Hang up the line when DTR is dropped
12.13 Nokia
Nokia Cellular Data Card for GSM and DCS1800
This one isn't really a modem as such (merely a data adaptor, the
modem is at the Mobile Switching Centre), but worth a mention, it
doesn't offer any form of data compression, but is useful if you're on
the road and need to connect. Make sure that the keyguard is not
active before trying to use it.
Tested on Cellnet GSM and Orange networks, it's a PCMCIA card that
plugs into the bottom of a Nokia 2100 series phone
AT&F S0=0 S35=6 S34=2
S0=0 Auto Answer off
S35=6 outgoing connection from Mobile Service Centre is using a V32 (9600) co
nnection.
S34=2 RTS/CTS flow control
12.14 Racal
From a user:
My modem is a model Racal Maxam V 9600 baud, about 2 years old.I have
been told that a Racal connected to a US Robotics the Racal can detect
a higher baud carrier as its own 9600 carrier. When connected you will
get lots of 8 bit characters and the modem will then drop the line.
This can be solved by forcing the modem to 9600 and not checking for
errors at this baud rate.
The command string is AT N0 F8 &E0 &W0 for a Racal:
N0 - Do not seek the baud rate
F8 - Force baud to 9600
&E0 - No error check
&W0 - Write change
12.15 Rockwell chipset modems
Rockwell chipsets are used in a variety of modems, including Supra,
SmartOne, Cardinal, BestData, SMART, Apex, ComOne
Important note regarding the "RPI" chipset:
Rockwell have released upon modem manufacturers a cut-down version of
their usual modem chipset, these "RPI chipset" modems do not offer
error correction or compression in the modem itself, but instead rely
on a software driver (availability as yet unknown) to perform these
functions. If you are using a RPI chipset, and do not have the
appropriate software driver (consult your modem manufacturer), you
will be unable to take advantage of modem compression of the data.
Here's the generic codes for Rockwell chipsets, your modem may vary
(See below for specific modems)
B0 v32bis modulation
E1 Local echo on
F0 Variable modem-to-modem speed negotiation
Q0 Modem sends responses
V1 Word response for errors
&K3 RTS/CTS Hardware handshaking
&S1 DSR not forced on
%C3 Compression on (V.42bis)
There is an "undocumented" feature present in the Supra V.32/V.32bis
FAX Modems that can help improve the quality of FAX and Data
transmissions.
The AT\E1 command is not documented in Supra's manuals, but is present
in the Rockwell V.32/V.32bis firmware/chipsets on which the Supra
V.32/V.32bis FAX Modems are based. This command is documented in the
RC96AC and RC144AC Modem Designer's Guide from Rockwell International.
DFI passport fax/modem
Amazingly, AT&F (restore to factory settings) is the optimum settings.
Pace Microlin
AT &K3 B0 E1 F0 Q0 V1 %C2 &C1 &D2 \J0 \N3
&K3 RTS/CTS Handshaking
B0 CCITT protocols
E1 Local Echo ON
F0 Negotiate connect speed - may want to use F10 <14.4> if saving for use w
ith demon only.
Q0 Enable result codes
V1 Verbose result codes
%C2 V42bis but no MNP5 compression
&C1 DCD follows carrier
&D2 hang up on DTR
\J0 fixed DTE speed
\N3 Autoreliable link - use \N2 to reject links negotiated without error cor
rection.
Useful bits
S30=18 Auto-disconnect after 180 seconds of inactivity
S95=32 Gives the compression protocol on connect message.
W1 Displays line speed, error correction protocol and DTE speed on connec
tion.
AT &W to save as default, or AT &W1 to save in second NVRAM
section for recall with ATZ1 as modem initialisation string.
Pace Mobifax
For connecting to Demon we recommend the following:
Command What it does
B0 Use V.32bis modulation/CCITT protocols rather than HST
&C1 Modem send CD (Carrier Detect) on connection
E1 Local echo ON
F0 Variable modem-to-modem speed negotiation
Q0 All result codes displayed
V1 Display result codes in verbal (not numerical) mode, e.g. OK not 0
X4 Gives full CONNECT string
&D2 Terminal sends DTR (Data Terminal Ready)
&S1 Data Set Ready (DSR) controlled by the computer
&K3 RTS/CTS flow-control
When done, type the command that saves the settings, AT&W, so that
they are remembered when the modem is reset.
Global Village
From a user:
The specs for AT commands for a Global Village PowerPort Silver and
Gold modems are as follows:
\N5 Set auto-reliable(V.42 LAPM only)
\Q3 Enable bi-directional hardware flow control
\J0 Disable port rate adjust;
serial port rate independent of the connection
%C1 Enable data compression
(V.42bis in LAPM)
<these following could be helpful...>
&W1 Save active configuration as User Profile 1
&Y1 Recall User Profile 1 on power up
&V1 View profile 1
Reveal
&F Restore factory settings
S0=0 Auto Answer switched off
Q0 Result code messages sent to machine
V1 Result code messages sent in English word format
&C1 DCD indicates on-line data carrier detected
&D2 Modem disconnects when DTR drops
L2 Medium speaker volume
E1 Command character echo enabled
\N4 V42 Reliable connections
\G1 Enable DCE flow control during normal link.
SmartOne
(also badged Best Data, CalCom)
&F Restore factory settings
B0 Select CCITT V.22 and V.21 mode
C1 Normal transmit carrier switching
E1 Command character echo enabled
F1 On-line state character echo disabled
Q0 Result code messages sent to machine
V1 Result code messages sent in English word format
&C1 DCD indicates on-line data carrier detected
&D2 Modem disconnects when DTR drops
&G2 1800 Hz Guard Tone
&K3 Enable CTS/RTS flow control
&Q6 Select Asynchronous operation in normal mode
&R0 CTS follows RTS
&S1 DSR turned off while carrier is lost
\G0 Disable XON/XOFF flow control
For v32bis (14,400 baud) models:
S37=11 Attempt to connect at 14400 BPS
Supra
Supra 14.4k fax modems need the ROM revision 1.70B or later but their
ROM revision number is odd. Revision 1.8 or 1.4 are also apparently
OK.
Information providing features
S95=41 Enable all CONNECT, PROTOCOL & COMPRESSION messages
L1M1 loudspeaker control (low volume, on until carrier)
Modem/PC signals
&D2 modem disconnects when DTR drops
&C1 DCD follows line carrier
&K3 Enable hardware flow control
Speed connection, reject bad lines
\N4 new models, only make LAPM Reliable connections
\N3 old models, make Autoreliable connections
S48=0 Disable negotiation, make V42 (LAPM) connection
N1 connect at highest shared data rate
Compression
%C2 new models, V.42bis (BTLZ) Enabled, (but not MNP)
S41=1 old models, enable data compression (BTLZ or MNP)
An initialisation string for this would be:
ATS95=41 L1M1&D2&C1&K3 \\N4 S48=0 N1 %C2
^note the double '\' is needed if typing this
into some dialer programs
To put this into the modem's memory (NVRAM) type at&w
Zoom modems
From one user comes this:
Zoom 14.4X FaxModem Settings
These setting are in use to connect to demon both via KA9Q and trumpet
winsock (SLIP). The settings enable 14400 BPS with V42 error
correction and V42bis data compression. In operation I achieve 2600
cps when obtaining mainly text news. Whilst I am sure the settings
work I do not vouch for the accuracy of my interpretation of what they
mean!!
To reset modem to stored profile:-
ATZ - sets to profile 0
ATZ0 - sets to profile 0
ATZ1 - sets to profile 1
To store current profile:-
AT&W0 store as profile 0
AT&W1 store as profile 1
For brevity I have left out setting that have no functional relevance.
Profile comments
E1 Command characters echoed
N0 Disable auto-mode detection; connection speed specified by register S37
Q0 Enable response to computer (DTE)
X3 Monitors busy tones; sends X2 messages
Y0 Disable long space disconnect
&C0 Forces RLSD (DCD) on
&D0 Data terminal ready options
&G2 Enable 1800Hz guard tone
&J0 (zero)Disable adjusting DTE speed
&K3 Enable RTS/CTS flow control. VITAL for slip connections such as Trumpet w
insock
&R1 CTS is always on in synchronous or drops if required by flow control in a
synchronous
&S1* DSR active after answer tone detected and inactive after carrier loss.
&T4 Responds to remote modem request for digital loopback.
Registers
Set using ATSn=v Sets register n to value v
S37 11 *
All lines with an * are for items than are altered from the factory
default settings.
We would recommend &d2 otherwise your modem may not hang up the line
when you have finished your call.
From yet another user: The best I've got so far for the Zoom 14.4X is
AT&F0W0&C1&D2%C2
&F0 (manufacturer's defaults, so we know where we are)
W0 (limit the messages coming from the modem)
(W1 gives lots of messages from the modem but causes problems for some peopl
e)
&C1&D2 (for hardware flow control)
%C2 (enable V42 bis but not MNP5)
12.16 Tricom
From a user:
I'm using a Tricom Pearl 144 from both an IBM Thinkpad and an Acorn
RiscPC.
I find that the initialisation string
AT&F&C1&D2M1L3S0=0
works reliably
&F factory setting
&C1 &D2 carrier detect and DSR as with other modems
M1 L3 loud speaker monitoring (feeble speaker & I'm rather deaf!)
S0=0 suppress auto answer
Because this starts from the factory setting, it ought to be
applicable however oddly the modem is set up.
Note that on the Tricom, the Z command terminates any command string,
so ATZS\ will *not* report the configuration.
12.17 Yoriko modems
Yorikos work OK with a simple AT &F &C1 &D2 set-up.
12.18 Zoltrix
These are one of our user's settings for a Zoltrix v32bis internal
fax/modem. He writes:
With X4, W1 and V1, I've managed to configure it very nicely to
re-dial if the line's are busy after only 5 seconds, report CONNECT,
PROTOCOL CARRIER, and BUSY
The only bit I'm vaguely unsure about is, whether disabling
compression (%c0 on mine), disables V42bis also, as I really only want
to knock out MNP 5. &Q9 I think attempts V42bis, falls back to
LAP-M+v42, then to normal.
An annoying feature is that at&v only digs out probably a quarter of
the settings - the '\' and '%' commands don't feature; some of them
appear extremely useful: %Q for instance purportedly reports line
signal quality, and %L received signal level, which I reckon might be
relevant to one recent spate of postings, and you can tune up V42bis
with others.
S86 stores a connection failure cause code.
OK
AT&V
ACTIVE PROFILE:
B0 E1 L0 M0 N1 Q0 T V1 W1 X4 Y0 &C1 &D2 &G0 &J0 &K3 &Q9 &R0 &S1 &T4 &X0 &Y0
S00:000 S01:000 S02:043 S03:013 S04:010 S05:008 S06:002 S07:060 S08:002 S09:006
S10:014 S11:095 S12:050 S18:000 S25:005 S26:001 S36:007 S37:000 S38:020 S44:003
S46:138 S48:007 S49:008 S50:255
Another user writes:
ROM revision (use ATI0 or similar to check) : See below
AT&Q5S48=7S46=138S95=46
ROM revision
------------
I have listed what comes out of ATI0 to ATI4 as ATI0
doesn't make sense!
ATI0 = 14400
ATI1 = 007
ATI2 = OK
ATI3 = V1.410-AP39
ATI4 = a007880284C6002F
bC60000000
r1005111151012004
r3000111170000000
Additional modem string information. (may be of some use)
&Q5 set error correction mode
causes the modem to try V42bis, then MNP5, then normal
connection
S48=7 enable V42 negotiation
S46=138 error correction with compression
S95=46 display extended result codes
so I can see that I've got error correction
and compression :-)
I also have a line
echo atz > com3:
in my demon.bat file to reset my modem as my fax software leaves it in
a bit of a state :-( Two 'init' lines don't seem to work (not that I'm
bothered!)
Yet another user writes:
This might be helpful if anyone calls using a
Zoltrix 28800/ Internal / Fax.
Setup straight from box, using a comms package.
Using factory settings,
AT&F Factory settings
S7=20 then alter s7 to = 20 ATS7=20
B0 then alter b1 to b0
&Q5 then alter &q6 to &q5
optional ATL1 to ATL2 ATL2 - modem volume to hear connect.
and then write these to the stored profiles
AT&W0
AT&W1
Zoltrix VFast modems can work at 28,800 with our USRobotics V34 modems
which we have started installing.
And from yet another user:
If the Zoltrix 28.8 you have is the same as mine - Rockwell WS-281412
Internal or a WS-2814EM2 then try either of the following init
strings...
AT&FE1Q0V1X4&C1&D2&K3&R0\N3S0=0
Works well in Trumpet and Turnpike - allows FoneCost to track DCD and
give an accurate log of billing only in trumpet though - usually gives
between 24000 and 28800 carrier. You can add speaker volume bits as
required.
AT&F0B0L3W1X4+MS=11,1,14400,28800
Short & sweet - forces between 14400 & 28800 carrier with V42
correction
One thing to watch for is making sure that &F or &F0 is the first
command ( to reset to factory) as the fax leaves the modem in a state,
usually with RTS/CTS left off and XON\XOFF on!
Being a US modem it doesn't seem to recognise the Busy state - I'm
sure there's a way to force it but I've still to find it :-( If anyone
out there has any ideas it would be great to be able to get away from
manual redials or waiting until the line drops.
12.19 Zyxel
From one of our users again:
The following "dial_cmd" is for a Zyxel U-1496E+ modem
"ATL2N1X7&G2*E1DT"
L2 sets a low (but not inaudible) speaker volume
N1 sets a low (but not inaudible) ringing volume
X7 sets result code options so that the "connect" message is, for example,
"CONNECT 14400/Arq/V42b"
&G2 enables 1800 Hz guard tone
*E1 terminate call if error control negotiation fails, i.e. insist on error-
control or end call
DT dial using DTMF tones
13. TESTING
To test out your setup you could try using ping. ping gate.demon.co.uk
whilst logged on directly to London or a vPoP should return a speed of
about 270ms on a fast link down to 1000ms on a slow link.
Try using ftp to ftp.demon.co.uk and downloading files from /pub/test.
There are files of varying contents that have also been compressed in
various ways. "empty" files are there so that you can test the maximum
throughput on blank data. "full" files contain a thorough mix of
characters and so little compression by your modem will be possible.
"regular" files are a mixture - just like this document or a Usenet
news message. Each of these three have been compressed using popular
methods and so you can try working on the compressed files as well if
you like. Try uploading these files to ftp.demon.co.uk:/incoming to
test the link in that direction as well.
Using a V.32bis modem, the maximum throughput you are likely to get on
a binary file is 1,600 cps. On an ASCII file the maximum is about
2,800 cps.
_________________________________________________________________
14. FINALLY
Please try to sort out your setup by following the above advice. If
you are still stuck then telephone the support line on 0181-371 1010
during support hours to see if further help can be offered. Full
support line details are available in /pub/doc/Welcome.txt.
Many thanks to the users who have helped to gather up much of this
information, often from poorly written manuals, and to John Navas for
his excellent high speed modem FAQ, available on the world wide web: .
http://web.aimnet.com/~jnavas/modem/faq.html