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1994-05-05
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Information, Instructions & Parameters for the ZOOM 28.8K Modem.
By: Joe Medeiros - (A.K.A. Joe Masters)
Z-288-2.TXT UPDATED & REVISED: 05/06/94
-----------------------------------------
This file was originally named Z-288-1.TXT I have revised this file for
several reasons; to add more information, to cover the configurations for
QModem and COMMUTE, and to fine tune a few command settings. If a future
revision is needed it will be named Z-288-3.TXT Hopefully that won't
happen until V.34 is standardized this summer.
PROLOGUE
--------
I am happy with my Zoom 28.8K modem. I understand how it works, how to
control it, and that it does have a few limitations, but if I had to buy
another modem tomorrow, I would buy another Zoom 28.8K modem.
The reason I have writen this file is to save others the weeks and months
of confusion that I lived with when I bought my first high speed modem two
years ago. I have attempted to begin this file at the point that Owner's
Manuals have left off.
-----------------------------------------------------------------------------
My source of reference for the information in this file is a combination of
Rockwell International's Modem Designer's Guides, Data Pump Manual, The AT
Command Reference Manual, my owning and setting up by trial & error a 14.4K
high speed modem two years ago, and applying that knowledge to the Zoom 28.8K
modem. So far Rockwell has been kind enough to supply me with over 400 pages
of technical specs about their 28.8K chips, data pump, and AT Commands to aid
me in this endeavor.
All 28.8K Modems with Rockwell RC288ACL/VFC and RC288ACi/VFC chips and the
manufacturer ROM chips (as of early 1994) are still in a developmental stage,
and will remain so until the CCITT formalizes the V.34 protocol this summer.
Rockwell and Hayes in a joint venture agreed on their own V.Fast protocol.
It is currently being marketed by both companies. The new Hayes 28.8K modems
also use Rockwell chips. This joint venture will force USRobotics to stop
marketing proprietory protocols and standardize with the rest of the industry.
The Zoom 28.8K and any 14.4K modem with Rockwell Chips are closely related.
Zoom did not bother to include an updated owners manual for the 28.8K. They
simply stuck a 4 page addendum into the old 14.4K manual. The 28.8K and
14.4K are cousins, BUT they are not "Kissin' Cousins!"
IMPORTANT! - BEFORE WE BEGIN - UNDERSTAND THIS:
-----------------------------------------------
Equate your modem to an automobile engine - "How does your engine run?" If
you don't put oil in it, and you don't have gasoline for it, then it isn't
going to run properly, if at all! All three are equally important. You need
all three together to have a working engine. In this case the modem is the
engine, the PROFILE is the oil, and the Init string is the gasoline. You
need properly configured Profiles and a correct init string for the modem to
run correctly. - Am I making my point here?
-----------------------------------------------------------------------------
ZOOM 28.8K SETUP INSTRUCTIONS:
------------------------------
First print this file, then follow these instructions:
(If you are using QModem proceed to the QModem instructions below.)
1 - Shut off XON/XOFF in terminal or BBS program.
2 - Shut off DSR/DTR in terminal or BBS program.
3 - Turn on CTS/RTS in terminal or BBS program.
4 - Change the Connect String word from CONNECT to CARRIER in your
terminal and/or BBS program. (The S95 register needs to see CARRIER)
5 - Set the baud rate speed of your terminal or BBS program to 115,200
baud, or 57,600 if 115,200 is not available as a choice.
(Some computers can't handle these speeds - if your are getting many
CRC errors with file transfers, use 38,400).
Run your terminal program type the following "One Time Setup Strings:"
(FOR QMODEM PRO AND TERMINATE SEE BELOW)
AT&F [ENTER]
AT%C0L1M1&C1&D2&S1S6=12S10=1S11=50S46=136S48=128S95=255&W0&W1 [ENTER]
OK, let's examine each command of the above instruction line:
AT&F - Resets modem to MOST factory default settings.
%C0 - Disables Modem Data Compression.
L1 - Loudness of modem speaker (range 0 - 3)
This is a personal preference setting.
M1 - Speaker on during modem negotiating only (range 0 - 3)
This is a personal preference setting.
&C1 - Follows the state of the data carrier from the remote modem.
&D2 - Determines action taken by the modem to the DTR.
&S1 - DSR operates in accordance with the EIA-232-D specification.
S6=12 - Longer delay. Needed to switch from voice directly to data connect
without having to hangup & redial the number.
S10=1 - Delays disconnect in case of loss of carrier detect. This loss
is mostly caused by marginal telephone lines. Low settings help
modem to hangup faster.
S11=50 - Forces modem to dial at the fastest speed possible.
S46=136 - Executes modem error correction with NO compression. (I will
explain more about modem compression in a later paragraph.)
S48=128 - Forces modem back to S36 register which is default 007.
Attempts MNP connection: if fails normal connection is established.
S95=255 - This setting gives maximum information upon connect with remote
modem. This setting is NOT documented in the Zoom manual.
(Look below for more info on this bitmapped setting.)
&W0 - Writes the settings into PROFILE 0 of the modem's NVRAM.
&W1 - Writes the settings into PROFILE 1 of the modem's NVRAM.
You only have to do the above ONCE - the profiles will store the data.
The reason you want to write the same settings to both Profiles is in case
you run a program that changes the settings without telling you that it
does modify Profile 0. Programs like Modem Doctor, QM Pro For Windows,
and Procomm For Windows all write to Profile 0. If this happens you can
quickly reprogram it by typing: AT&F [ENTER] ATZ1 [ENTER] AT&W0 [ENTER]
INIT STRING SETUP
-----------------
NEXT USE THIS MODEM INIT STRING: AT&F^M~~~ATZ0^M~~~~AT%C0%E2^M
OK, let's examine each command of the Init. String:
AT&F - Resets the modem to all factory default settings.
ATZ0 - Uses the settings in Profile 0 (ATZ1 uses Profile 1 settings)
%C0 - Disables Modem Data Compression.
%E2 - Turns on the line quality monitoring, and fallback/fall forward.
This is a better choice than %E1 or %E3 because RETRAIN only
trys to initiate recovery at the previous connect speed.
%E0 disables monitoring so you don't want that either.
The Init string must be run each time you start the modem - it is normally
configured in your terminal or BBS program - You should NOT have to type
it in each time you run start using the modem.
After you configure your modem with these instructions, you should see the
following when you start your terminal program:
AT&F
OK
ATZ
OK
AT%C0%E2
OK
Next Type: AT&V [ENTER]
You should now see the following settings in your profiles. If any of
the settings are different than what is below, change them, and save
them using: AT&W0 (For PROFILE 0) and AT&W1 (For PROFILE 1).
ACTIVE PROFILE:
B1 E1 L1 M1 N1 Q0 T V1 W0 X4 Y0 &C1 &D2 &G0 &J0 &K3 &Q5 &R1 &S1 &T4 &X0 &Y0
S00:000 S01:000 S02:043 S03:013 S04:010 S05:008 S06:002 S07:065 S08:002 S09:006
S10:001 S11:050 S12:050 S18:000 S25:005 S26:001 S36:007 S37:000 S38:020 S44:020
S46:136 S48:128 S95:255
STORED PROFILE 0:
B1 E1 L1 M1 N1 Q0 T V1 W0 X4 Y0 &C1 &D2 &G0 &J0 &K3 &Q5 &R1 &S1 &T4 &X0
S00:000 S02:043 S06:002 S07:065 S08:002 S09:006 S10:001 S11:050 S12:050 S18:000
S36:007 S37:000 S40:105 S41:192 S46:136 S95:255
STORED PROFILE 1:
B1 E1 L1 M1 N1 Q0 T V1 W0 X4 Y0 &C1 &D2 &G0 &J0 &K3 &Q5 &R1 &S1 &T4 &X0
S00:000 S02:043 S06:002 S07:065 S08:002 S09:006 S10:001 S11:050 S12:050 S18:000
S36:007 S37:000 S40:105 S41:192 S46:136 S95:255
-----------------------------------------------------------------------------
IF YOU USE QMODEM PRO
---------------------
First, I do NOT like QModem Pro. One of the resons is that it configures
differently from most other terminal programs. It doesn't use standard
pauses. The standard half second pause is ~ but Mustang Software
decided to use ^~ as it's half second pause.
You can manually type it in whil in the terminal mode, BUT it won't run
as an init string.
That is simply my opinion - If you like QMP then follow these instructions:
While running QMP terminal, type these strings:
AT&F [ENTER]
AT%C0L1M1&C1&D2&S1S6=12S10=1S11=50S46=136S48=128S95=255&W0&W1 [ENTER]
If the above gives you get an error then enter one command at a time:
AT&F [ENTER]
AT%C0 [ENTER]
ATL1 [ENTER]
ATM1 [ENTER]
AT&C1 [ENTER]
AT&D2 [ENTER]
AT&S1 [ENTER]
ATS6=12 [ENTER]
ATS10=1 [ENTER]
ATS11=50 [ENTER]
ATS46=136 [ENTER]
ATS48=128 [ENTER]
ATS95=255 [ENTER]
AT&W0 [ENTER]
AT&W1 [ENTER]
After you have configured and saved your profiles in QModem, as shown
above, use the following as your init string:
AT&F^M^~^~^~ATZ^M^~^~^~^~AT%C0%E2^M
QM Pro for Windows has a file named QMPRO.DDT
- put the following data lines into it:
@ZOOM/Modem 28.8K with Fax & V.42bis
ShortName=ZOOM 28.8K Modem
ModemReset=AT&F^M^~^~^~ATZ^M^~^~^~^~AT%C0%E2^M
ModemInit=AT&F^M^~^~^~^~
ModemInit=AT%C0L1M1&C1&D2&S1S6=12S&=65S10=1^M^~^~^~^~
ModemInit=ATS11=50S46=136S48=128S95=255^M^~^~^~^~
ModemInit=AT&W0&W1^M
PostSet=Your Zoom 28.8K is ready to go!
PostSet=Be sure to specify this device for each of your dialing
PostSet=directory entries. Also double check the configuration with
PostSet=your modem's
PostSet=Set DTE speed to 115000 for use as FAX device.
In the future you will be able to choose this device from the QModem Pro
menu. Pick Device, then Quick Configure.
(Another reason that I do not like QMP is the above configuration. The
"Modem Reset" is actually the Modem Init. The FOUR Modem Inits that I
had to use are REALLY "One Time Setup Strings," and they were a BITCH
to debug. You only need 1 long "One Time Setup String" with Telix.)
ALL OTHER INFORMATION IN THIS FILE USING ~ AS PAUSE MUST BE SUBSTITUTED
WITH ^~ ELSE QMODEM WON'T ACCEPT IT. CHANGE EACH ~ TO ^~ YOU
ALSO MAY HAVE TO PUT ADDITIONAL ^~ PAUSES INTO EACH STRING UNTIL QMODEM
ACCEPTS IT.
-----------------------------------------------------------------------------
IF YOU USE TERMINATE
--------------------
Run your terminal program type the following "One Time Setup Strings:"
AT&F [ENTER]
AT%C0L1M1&C1&D2&S1S6=12S10=1S11=50 [ENTER]
ATS46=136S48=128S95=255&W0&W1 [ENTER]
(The L1 and M1 are personal preference settings.)
After you have configured and saved these profiles in Terminate,
as shown above, NEXT USE THIS AS YOUR MODEM INIT STRING:
AT&F^M~~~ATZ0^M~~~~AT%C0%E2^M
-----------------------------------------------------------------------------
COMMUTE
-------
If you use Commute, add the following to your COMMUTE.MDM file. The file
is in alphanetical order, so find the section near the end with the Zoom
modems and put it there. After you add it, start Commute, reconfigure it
by choosing the Zoom V.28 modem.
/* 6-16B */
/* Added 24 Apr 1994 by Joe Masters*/
/MN="Zoom V.2^8.8K Modem"
/MI="AT&F^M~~ATZ^M~~~~AT%C0%E2^M"
/MD="ATDT"
/MA="ATS0=1^M"
/MH="~+++~~~ATZ^M~"
/AS=1
/BR=57600
NOTE: Change the /MD="ATDT" to /MD="ATDT*70," to kill "Call Waiting."
-----------------------------------------------------------------------------
WHICH PROTOCOL TO USE:
----------------------
LAP-M is usually the protocol of choice when setting up a modem. There is not
a major difference in the performance of the two, but I use MNP4 because it is
2 - 3% more efficient. In order to test the two protocols, I connected to a
BBS and downloaded the same file twice, once with LAP-M, and once with MNP4.
The following is the actual CAPTURE file of the two tests:
------------------------------------
| TEST #1 USING LAP-M |
------------------------------------
PROTOCOL: LAP-M
COMPRESSION: NONE
CONNECT 14400/ARQ
CONNECT 14400/ARQ/V32/LAPM
CONNECT 38400 / 04-24-94 (10:43:24)
*Error Correcting Modem Detected*
Channel 1(R) Communications [Hayes Ultima V.32bis]
PCBoard (R) v15.1/250 - Node 52 - TFE7AA9E9988
(9 min. left) [Node 52] Free (5) Conference Command? d
(1) Enter the filename to Download Enter = none? waf165.zip
Checking file transfer request. Please wait, Joe ...
(1) WAF165.ZIP 510372 bytes, 5.4 minutes (approximate) FREE / NO TIME
(2) Enter the filename to Download Enter = none?
Batch Download Time: 5.4 minutes (approximate)
Batch Download Size: 510372 bytes (499 blocks)
Batch Protocol Type: Zmodem Batch
(Ready to Send in Batch Mode)
(A)bort, (E)dit, (G)oodbye, (L)ist, (P)rotocol, (Enter)=continue? ()
Sending File(s) - Start your download ...
rz **B0080000000dd38 è
Batch Transfer Ended. (Files: 1 Bytes: 510372 Avg. CPS: 1673)
Press (Enter) to continue?
-----------------------------------------------------------------------------
----------------------------------
| TEST #2 USING MNP4 |
----------------------------------
PROTOCOL: ALT
COMPRESSION: NONE
CONNECT 14400/ARQ
CONNECT 14400/ARQ/V32/MNP
CONNECT 38400 / 04-24-94 (11:10:44)
*Error Correcting Modem Detected*
Channel 1(R) Communications [USR V.32bis]
PCBoard (R) v15.1/250 - Node 39 - TFE7AA9E9988
(2 min. left) [Node 52] Free (5) Conference Command? d
(1) Enter the filename to Download Enter = none? waf165.zip
Checking file transfer request. Please wait, Joe ...
(1) WAF165.ZIP 510372 bytes, 5.4 minutes (approximate) FREE / NO TIME
(2) Enter the filename to Download Enter = none?
Batch Download Time: 5.4 minutes (approximate)
Batch Download Size: 510372 bytes (499 blocks)
Batch Protocol Type: Zmodem Batch
(Ready to Send in Batch Mode)
(A)bort, (E)dit, (G)oodbye, (L)ist, (P)rotocol, (Enter)=continue? ()
Sending File(s) - Start your download ...
rz **B0080000000dd38 è
Batch Transfer Ended. (Files: 1 Bytes: 510372 Avg. CPS: 1704)
Press (Enter) to continue?
I have repeaated this test several times over the last two years. I used
Telix and GSZ ZModem with MobyTurbo with these tests. MNP4 has ALWAYS
beat LAP-M by about 3%
-----------------------------------------------------------------------------
MODEM SPEEDS AND MODEM TERMS THAT OFTEN GET CONFUSED
----------------------------------------------------
There alway seems to be much confusion over terms that relate to speed and
exactly what is getting measured. Here are some terms and diagram to help
you better understand modems.
DCE (Data Communication Equipment) rate: The transmission speed of the
interface between two modems. The DCE rate and BPS are synonymous.
DTE (Data Terminal Equipment) rate: The transmission speed of the interface
between a computer/terminal and it's modem. Includes the RS-232 Serial ports.
Baud rate is frequently cited in this interface (*as is bps*), all of which is
depicted on Fig. 1. Note DTE/baud exists on both ends, while DCE/bps is
between the modems. DTE is often called the Port area (and Port Speed) since
this is where the Serial Ports are.
+--------+ +--------+
| | | |
|Computer| DTE- DCE- DTE- |Computer|
| | Rate +-------+ Rate +-------+ Rate | |
| #1 |==========| Modem |=============| Modem |==========| #2 |
| | +-- 1 --+ ^ +-- 2 --+ | |
+--------+ Telephone +--------+
Line
BAUD RATE: The actual rate of signal transitions per second. Since each
signal may represent more than one bit, it is not the same as BPS.
BPS or Bits Per Second: The number of data bits per second transmitted
between two modems. Sometimes incorrectly called the baud rate.
(See Baud Rate above) In common parlance, BAUD and BPS have become
synonymous, but the two terms are completely different.
THROUGHPUT: The DCE rate expressed in cps (Characters/second = bytes/sec).
In a modern 9600 bps modem (often incorrectly called a 9600 baud modem) the
signal rate is actually 2400 baud. It is encoded with four data bits per baud,
resulting in a DCE rate of 9600 bps. The 14,400 bps modem is much the same,
but encoded with 6 data bits per baud.
-----------------------------------------------------------------------------
Other items you should fully realize AND understand:
----------------------------------------------------
A - These commands/settings were not devised nor do they belong to Zoom.
Rockwell International devised the chip, and programmed it with Hayes
AT Commands before they sold it Zoom. Rockwell is the ultimate authority
on information about this chip, not Zoom. The new Hayes modems also
now use Rockwell chips.
B - The settings that I use shut off modem compression. You do NOT want any
modem compression when transfering ZIP, ARJ, LHZ, ARJ, etc. files. These
files have already been compressed, and trying to recompress them again.
V.42BIS will slow down the file transfer slightly. MNP5 will slow it down
significently. Only if you are transfering text, acsii, or uncompressed
binary files does modem compression ever increase file transfer speed.
-----------------------------------------------------------------------------
UNDERSTANDING THE S95 REGISTER
------------------------------
You ask, "how do you use it?" S95 is bit mapped. This is the power table:
Bit 0 is 000000001 which = 1 CONNECT result code speed instead of DTE speed
Bit 1 is 000000010 which = 2 Append/ARQ to CONNECT XXXX result code in
error-correction mode.
Bit 2 is 000000100 which = 4 Enable CARRIER XXXX result code.
Bit 3 is 000001000 which = 8 Enable PROTOCOL XXXX result code.
Bit 4 is 000010000 which = 16 (reserved)
Bit 5 is 000100000 which = 32 Enable COMPRESSION result code.
Bit 6 is 001000000 which = 64 (reserved)
Bit 7 is 010000000 which = 128 (reserved)
To get the desired S95 register result code, add the bit #'s you want. That
means the numbers you want to add are any combination of 1, 2, 4, 8, 16, 32,
64, and 128. If your S95 register is currently S95=3 then you are using
Bit 0 and Bit 1. Can you get more information when the modems connect? Yes!
Only a moron would want to permanently set Bit 0 to S95=1 (the DCE speed.)
The 255 that I choose uses Bits 0 - 7. Can you use others? Sure, but using
or not using the reserved Bits 16, 64, and/or 128 doesn't matter. You can use
S95=47, 127, 191, or 255 and get the same EXACT results. If Rockwell ever
decides to use the reserved bits, ATS95=255 will address them all.
Again, keep in mind if you do not change to word CONNECT to CARRIER in
your terminal or BBS program, you won't see any Connect Results anyway.
-----------------------------------------------------------------------------
TO SWITCH BETWEEN MNP4, LAP-M, V.42BIS, and CLASS 5
---------------------------------------------------
To turn on and switch between MNP4, LAP-M, V.42BIS, and CLASS 5,
use the following inits:
For LAP-M No Compression: AT&F^M~~ATZ^M~~~~ATS46=136S48=7%C0%E2^M
For LAP-M with V.42BIS Compression: AT&F^M~~ATZ^M~~~~ATS46=138S48=7%C2%E2^M
For MNP4 with CLASS 5 Compression: AT&F^M~~ATZ^M~~~~AT%C1%E2^M
For MNP4 with V.42BIS Compression: AT&F^M~~ATZ^M~~~~AT%C2\N5^M
(Some remote modems will not accept MNP4 and LAP-M together.)
To return to normal MNP4 - No Compression: AT&F^M~~ATZ^M~~~~AT%C0%E2^M
The ^M is a carrier return command = [ENTER]
The ~ are 1/2 second waits giving the modem time to respond to each
command. ( For QModem use ^~ for each ~ )
These strings may be used as keystroke marcos in your terminal program
to reprogram your modem by pressing one key. I have setup my F9 - F12
keys in Telix to do exactly that.
You need to set up the Zoom 28.8K with the above instructions about the
Profiles BEFORE you attempt to use these strings. Some of the settings
are dependent upon the profiles.
-----------------------------------------------------------------------------
NVRAM - WHAT SETTINGS IT WILL STORE
-----------------------------------
B, E, L, M, N, P (or T) < choose PULSE or TONE > T, Q, V, W, X, Y,
&C, &D, &G, &J, &K, &P, &Q, &R, &S, &T, &X, &Y,
S0, S6 - S12, S14, S15, S18, S21, S22, S23, S36, S37, S40, S41, S44, S46
S48, S95
Notice NVRAM will NOT store %E2. That is why this switch must be included
in each Init String.
-----------------------------------------------------------------------------
A FEW MORE TERMS EXPLAINED
--------------------------
LAPM
----
Link Access Procedure for Modems, the primary error control protocol
method defined in CCITT V.42 (now ITU-T V.42).
MNP5
----
Microcom Networking Protocol- Service Level 5, a data compression
protocol used in conjunction with error control. It can theorectically
deleiver a throughput increase of approximately 2:1. When presented with
data that has been pre-compressed, MNP5 actually expands the size of the
data stream, thus retarding throughput.
V.42
----
CCITT Recommendation V.42 (now ITU-T V.42) is a error control
negotiation protocol which defines LAP-M as the preferable and primary
method of error control, but includes a workalike to MNP2-4 as a
fallback compatibility mode.
V.42bis
-------
CCITT recommendation V.42bis (now ITU-T V.42bis) is a data compression
protocol that is used in conjunction with error corrected links. As
typically implemented, it has the theorectical capability of delivering
a 4:1 increase in throughput. It also has the capability of operating in
a "transparent" mode which will not allow it to expand data presented to
it which has already been compressed.
-----------------------------------------------------------------------------
DISCONNECT PROBLEMS
-------------------
Zoom modems sometimes have a problem disconnecting from other modems. I am
experimenting with two different work around init strings for this. Both
seem 95% effective. For some reason Zoom modems SOMETIMES do not recognize
the +++ to send it back to the command mode, so when the +++ATH is issued,
the modem doesn't respond because it is still in the on-line state.
The first work around or fix, is simply sending a control code ahead of the
normal hangup string in an attempt to regain the modem's attention, and
slightly adjusting the normal hangup string.
The second work around hangup string combines two concepts; first it sends
a control code in an attempt to regain the modem's attention, then the second
part uses the modem's Z command rather than the H command to do the disconnect.
The Z command makes the same relay switch click that you hear when you press
your computer's reset switch.
The S10 register is also set to 1 to disconnect as soon as possible in case
the hangup string fails.
This fix should also work on other Zoom model modems, but I have not tested
it. I do not know if this fix will work on an external modems, but it won't
hurt to give it a try. 95% of the time, I am now disconnecting within 1.5
seconds!
WORK AROUND #1
--------------
Make sure S10=1
Change your hangup string to ^[~+++ATH^M
If your terminal program doesn't like the ^[~+++ATH^M then try ^[~+++~ATH^M
or ^[~+++~~ATH^M If you are still having a problem getting you terminal
program to configure, you may want to experiment with ^[~+~+~+~ATH^M.
Both of these strings are working equally well for me. Try them both and
decide which one works best for you.
WORK AROUND #2
--------------
Make sure S10=1
Change your hangup string to ^[~+++ATZ^M
If your terminal program doesn't like the ^[~+++ATZ^M then try ^[~+++~ATZ^M
or ^[~+++~~ATZ^M If you are still having a problem getting your terminal
program to configure, you may want to experiment with ^[~+~+~+~ATZ^M.
-----------------------------------------------------------------------------
OTHER INFORMATION ABOUT ATZ
---------------------------
ATZ is the same as ATZ0. There is also an ATZ1. The 0 and 1 stipulate
which Profile is to be read and used as your active profile settings.
When you use ATZ the modem also performs FOUR diagnostic tests:
1 - RAM Test
2 - ROM Test
3 - NVRAM Test
4 - Lamp Test (external modem)
-----------------------------------------------------------------------------
MODEM IDENTIFICATION INFORMATION
--------------------------------
There are several commands that can be typed into the modem to give you
specific information about it.
ATI0 - Reports product code
ATI1 - Reports a precomputed ROM checksum
ATI2 - Computes checksum, compares with value in ROM,
and returns OK or ERROR
ATI3 - Reports firmware revision code
ATI4 - Reports Zoom faxmodem identifier string
ATI5 - Reports country code parameter
ATI6 - Reports data pump model and revision code
ATI7 - Used in World Class modems only - otherwise ERROR
My modem gave the following responses:
COMMAND RESPONSE MY MISC NOTES
------- -------- -------------
ATI0 28800 Meaning 28.8K modem
ATI1 007 My ROM Checksum
ATI2 OK My ROM Checksum test result
ATI3 V0.510-VFP - 01C My ROM Verison
ATI4 a007880284C6002F
bC60000000
r1005111151012004
r3000111170000000
ATI5 022 (022 = United States)
ATI6 RC288DPi Rev 04BB (data pump model & internal
code revision)
ATI7 ERROR Proper response for non-World Class
-----------------------------------------------------------------------------
LINE NOISE
----------
I CAN NOT EXPRESS HOW IMPORTANT THIS SECTION REGARDING LINE NOISE IS!
---------------------------------------------------------------------
Telephone Line noise is critical to your connect speed. Marginal lines
will prevent you from obtaining any speeds at, or near 28.8K. The area
that I live in, 20 miles north of Boston, MA., is plagued with corroded
telephone wires and antiquated mechanical relays & switches.
REMEMBER, higher connect speeds pass data at higher speeds. The faster the
data is traveling, the more susceptible it becomes to line noise! Line noise
a disease. It is the "AIDS" of telecommunications!
When I got my first 14.4K high speed modem two years ago, I kept saying,
"What the f___ is wrong here?" Then it dawned on me to start keeping track
of the line quality of my CONNECTS with the AT%Q command. Was I in for a
shock! The my owners manual said that "NORMAL CONNECTIONS RANGE FROM 0 to 2,
AND APPROACHES 8 FOR PROGRESSIVELY POORER CONNECTIONS." If I get down to the
10 to 20 range with the crap lines in my town I am happy! Many times I have
connections that go as high as 50, 100, and 127 using the AT%Q I have seen
127! 127 is as high as the modem will measure. That is SERIOUS line noise!
If you get 000 line noise then you have lost the CONNECT - the manual was
wrong. It should have read: " GOOD CONNECTIONS RANGE FROM 1 to 3, AND
APPROACHES 15 FOR PROGRESSIVELY POORER CONNECTIONS." Around 50 or above
means you are about to be disconnected.
I have seen hundreds of high speed modem owners complaining in the national
High Speed Modem Forums and on Zoom BBS about how many modems are junk. It
is NOT the modem, it is the Ma Bell telephone lines. People get disconnected
so they change a register and call back. When they call back the second time
they do not get disconnected so they assume that whatever they changed worked.
- That is NOT what happened. If they called back without making any changes
they still would NOT have been disconnected because they were on a different
and better quality telephone trunk line.
Modems with Rockwell RC96xx, RC144xx, RC24xx and RC288xx chips all have a
fantastic feature, an E.Q.M.! It will actually measure line noise and
allow you to observe it with the E.Q.M. ("Eye Quality Monitor.")
Before you condemn your high speed modem, use the following test when you
have connected to a BBS. You may be in for a very rude awakening concerning
the poor quality of your telephone lines!
Test Procedure:
1 - Start your terminal program and type ATF19 - this forces 28.8K
2 - CONNECT to another modem. (Hope to get an unstable connection - with
lots of garbage or a screen that keeps stopping. That's what this
test is all about.)
3 - TYPE: +++ (You will receive an OK - meaning you are in Command Mode)
4 - TYPE: AT%Q <ENTER> (You will see a number.)
5 - TYPE: A/ (Do A/ repeatedly and quickly about 25 - 30 times.)
6 - Watch the number that keeps appearing after each A/
The number should be anywhere from 001 to 010. If it says over
40 you have serious line noise. It it gets near 60 you are
going to loose the CARRIER DETECT. If it drops to 000 the modems
have temporarily lost their ability to communicate.
7 - TYPE: ATO to return to the on-line state and continue with the BBS.
^ that is the letter O not a 0 (zero.)
8 - INSTEAD OF STEP 7 - TYPE ATO1 and watch your modem renegotaite.
^ that is the letter O not a 0 (zero.)
Try this test with a BBS that you usually have no problem connecting with.
The AT%Q will probably show readings about 002 to 009. Next call a BBS or
two that you usually have problems obtaining high speeds with. You will
probably see much higher readings with the test. I have seen normal readings
for 20 or 30 seconds, then it sky rockets to 100 or more for a few seconds.
This proves your problem is with line noise, not the modem.
I called NYNEX repair service for over two years about my line noise
problems. I was repeatedly told that I needed "a new pair," but there
were none available in my area. I received no satisfaction from them.
I finally called the President of NYNEX in Post Office Square, in Boston,
MA. His executive secretary apologized for my problems and promised me
that it would be rectified. The next day I had FIVE telephone trucks in
front of my house! The workers acted like I was God! "Yes Sir, we have
been instructed to free up a new pair for you!" 80% of my problems went
away. It is still not perfect, but it is far better than I had ever had.
The ultimate answer is called fiber optic lines, and solid state switching
relays, but they are not available in my area.
THE ULTIMATE MODEM CONNECT SPEED TEST:
--------------------------------------
There is another way to test your CONNECT modem speed and to completely
eliminate the "Is it line noise" question. Bring your computer to the home
of another person who has a 28.8K modem. Rather than plugging your modem
into a telephone wall jack, plug it directly into his modem jack. There
will be no dial tone, but you won't need one. The connect will be
instantaneous. There will be NO line noise. There will be no chance of
any external interference.
1 - Run a terminal program on both computers.
2 - On the first computer type: ATDT [ENTER]
3 - On the other computer type: ATA [ENTER]
This will affect the CONNECT.
If you still have a problem connecting at 26.4K and 28.8K then you can blame
it on the modems, but not until you do this direct modem to modem test.
In short, STOP blaming your modem as being crap until you understand how
to set it up, how to control it, and you have run these tests. If line
noise is your problem, then go after your local telephone company. You
should also be aware that your telephone company will probably tell you
that they do not guarantee noise free telecommunications lines, they just
guarantee good quality voice lines.
-----------------------------------------------------------------------------
BUILDING A NOISE FILTER
-----------------------
Another way to help line noise is with an in-line filter. I have done a
couple of hit or miss filters that have had some effect on line noise, but
not entirely eliminated it. The way to resolve the line noise problem is
for Ma Bell to replace it's antiquated and corroded wires with fiber optics.
That will take a few years. A more complex filter may help, but I do not
have the time, energy or patience to design one. The following has done
an adequate job for me.
:-------------:
< RED WIRE > ------------------------------------------| :
| | | : Z O O M :
= = X : :
| | | : M O D E M :
< GREEN WIRE > ------------------------------ 0 ---------| :
:-------------:
|
The = represents the capacitors.
|
|
The X represents the 12K resistor.
|
The --0-- represents the 12 volt miniature lamp. (light bulb)
Do not connect anything to the yellow and/or black wires. Place the
capacitors, resistor, and the miniature lamp as close to the modem as you
can. The miniature lamp has two wires running out of it (red & white.)
It does not matter which way you hook them up.
When you buy the resistor, I do not believe that the value is critical.
I used a 12K resistor but a 10K to 14K might do just as well. A rating
of 1/2 watt seems OK but if you want to put in a 1 watt resistor, that
wouldn't hurt either.
The value of the capacitors are .01 Microfarads - ceramic, non polarized.
The total cash outlay for these parts will be under $4.00. Not too much
to spend to help reduce such an irritating problem.
The light will illuminate when the modem goes off hook. This is an extra
feature and a needed one for internal modems.
LINE FILTER #2 (not my design)
--------------
100 ohm 1/2W ___________
------------- Red __________/\ /\ ______/\ /\ _______|Phone |
\/ \/ \/ \/ |Jack in |
------------- Blk ----- N/C 5K Pot |Parallel |
|with |
------------- Yel ----- N/C 1.0 mf (200V) _____|modem jack|
____||____ / |__________|
------------- Grn ____________/ || \________/ | | | |
\_______||_/ | | | |
|| | | | |
1.0 mf (200V) To modem phone jack
BUYING A NOISE FILTER
---------------------
AT&T sells a telephone line filter. The model number is Z100A. Call your
local AT&T Phone Center for the price. Buy it and try it. If it doesn't
help, return it and get a refund!
-----------------------------------------------------------------------------
CALLER ID INFO
--------------
! ! ! S U R P R I S E ! ! !
There is no documentation in the current Zoom manual for this, but the new
Rockwell 28.8K chip supports "Caller ID". I am not sure however if the Zoom
BIOS chip or modem is setup for it, or if an additional chip is needed.
It may also be possible to software support it. Zoom may also introduce a
more expensive model which will support Caller ID. Since I do not have
Caller ID I can not run any tests, but here are the Rockwell commands:
COMMANDS
--------
AT#CID=0 - Disables Caller ID. (Default)
AT#CID=1 - Enables Caller ID with formatted presentation to the DTE.
The modem will present the data intems in a <Tag><Value>
pair format. The expected pairs are data, time, caller code
(telephone number), and name.
AT#CID=2 - Enables Called ID with unformatted format to the DTE. The
modem will present the entire packet of information, excluding
the leading U's in ASCII printable hex numbers.
INQUIRIES
---------
AT#CID? - Retrieves the current Caller ID mode from the modem.
AT#CID=? - Returns the mode capabilities of the modem in a list with each
element seperated by commas.
FORMATTED FORM REPORTING
------------------------
The modem presents the data in the <Tag> = <Value> pair format as described
in the data table below. Spaces are presented on both sides of the equal
sign.
TAG DESCRIPTION
--- -----------
DATE DATE=MMDD where MM is the month number (01 to 12)
and DD is the day number (01 to 31.)
TIME TIME=HHMM where HH is the hour number (00 to 23)
and MM is the minute number (00 to 59.)
NMBR NMBR=<number> or P or O where <number> is the telephone
number of the caller, where P indicates that the calling
number information is not available since the originating
caller has requested private service, and where O indicates
that the calling number information is not available or out
of service at the calling location.
NAME NAME=<listing name> where <listing name> is the subscription
name.
MESG MESG=<date tag><length of message><date><checksum> in
printable ASCII hex numbers. This tag indicates a data
item not listed above. The message is only possible for
Multiple Message Format.
NOTES
-----
1 - The modem does not present any Caller ID information if the DCE detects
a checksum error in the Caller ID packet.
2 - In the event of an unrecognized data tag, the modem will present the
data in ASCII hex numbers following the MESG tag.
EXAMPLE OF FORMATTED FORM REPORTING
-----------------------------------
1 - The following example illustrates the standard Caller ID message packet.
RING
DATE = 0321
TIME = 1405
NMBR = 5045551234
NAME = A J CONSUMER
RING
RING
2 - The following example illustrates the case where the tag of the packet
is not recognized by the modem.
RING
MESG = 060342424231
RING
RING
UNFORMATTED FORM REPORTING
--------------------------
The modem presents all information and packet control information found
in the message. The modem, however, excludes the leading U's (channel
seizure information) from the presentation. The packet is presented in
ASCII printable hex numbers, the modem does not insert spaces, or line
feeds, for formatting between bytes or words of the packet.
EXAMPLE OF UNFORMATTED REPORTING
--------------------------------
RING
041230333232323430353931435353132333435
RING
RING
-----------------------------------------------------------------------------
EPILOGUE: - DOES THE ZOOM 28.8K MODEM HAVE ANY BUGS IN IT?
--------------------------------------------------------------
Yes, - This file is not a total defense of the Zoom modem. I have found
four problems with the modem so far. ( My ROM Version is V0.510-VFP - 01C
To find your ROM Version, start your terminal program, type: ATI3 [ENTER]
1 - My modem occasionally has difficulty sensing a busy sound and recycling
to redial.
2 - I already addressed the difficulty the modem sometimes encounters when
hanging up. This problem appears to happen when attempting to hangup
with USRobotics modems. I believe this problem can be fixed in the ROM.
My work around hangup strings are handling this for now.
3 - When I dial a number and it is busy, during the pause before redial I
can hear an AM radio station coming from the modem speaker! The station
transmitter is located about 5 air miles from my home. It transmits on
680Khz. The modem still dials properly but it is strange hearing those
voices while it is waiting to redial! This is known as R.F.I. (Radio
Frequency Interference.)
4 - I have had much difficulty connecting at 26.4K and 28.8K. This
problem will be addressed by the CCITT this summer when V.34 becomes
standardized. Rockwell may be forced to redesign areas of their RC288
chips to be more noise immune, or it may be as easy as Zoom simply
doing a ROM update to upgrade it to V.34. The price for this upgrade
has been rumored at $40 - $50. Line noise problems may also be ignored
and I will have to continue to live with it. In either case, I remain
happy connecting at 24K and getting 2800 CPS transfers on compressed files.
The first two problems are in the ROM of the modem and can be corrected with
a ROM upgrade. The R.F.I. problem can be easily corrected with a ferite bead
or two. Will Zoom upgrade the ROM before the CCITT formalizes V.34? They
have already upgraded once. My INSIDE sources tell me that a Vers. 1.0 ROM is
already in the testing stages. We will have to wait until it is debugged.
That's all for now...
Last Update: 05/06/94
<EOF>