SGI Developer Toolbox 6.1/SGI Developer Toolbox 6.1 - Disc 4.iso/public/fax/src/relnotes/ch7.cmm

Text File | 1994-08-01 | 13KB | 346 lines

.ds FF Flex\s-1FAX\s+1
.nr H1 6
.H 1 "Modem Bugs and Gotchas"
This section contains information about modem bugs and gotchas that have
been gleaned from direct experiences making the \*(FF code work with
the modems.
These problems are based on my experiences or on the experiences
of others that have worked with this software.
One should always check the version of the firmware listed.
Note also that if a modem is not listed here then I have \fBnot\fP tried it.
This list is sorted in alphabetical order.
.H 2 "Class 1 Modems"
.H 3 "AT&T Paradyne DataPort 14.4 (C01.22.00)"
.BL
.LI
Received \s-1HDLC\s+1 frames do not include the \s-1FCS\s+1 bytes
in firmware revisions before C01.33.00.
To workaround this problem the Class1FrameOverhead configuration
parameter should be set to 2.
.LI
In firmware revisions prior to C01.45.00,
carrier is sometimes dropped without notice during receive.
.LI
The command "\s-1ATH+FCLASS=0;A\s+1" does not do the right thing because the
command parser does not parse the ";A".
.LE
.H 3 "Digicom Scout+ (2A19/2931)"
.BL
.LI
\s-1ATS17=2\s+1 can be used to force 1300 Hz \s-1CNG\s+1 tones to be sent (the
register is not documented).
.LI
\s-1RTS/CTS\s+1 flow control is not honored while sending page data;
software flow control must be used (*F2).
This is possible in later firmware revisions by setting register \s-1S24\s+1:
.TS
l l.
\s-1S24=0\s+1    \s-1XON/XOFF\s+1 forced in fax mode
\s-1S24=1\s+1    \s-1RTS/CTS\s+1 forced in fax mode
\s-1S24=2\s+1    same as *F from init string
.TE
.AL 1 +5
.LI
\s-1S24\s+1 is not permanent.
.LI
On power on \s-1S24=0\s+1.
.LI
After each disconnection, \s-1S24=0\s+1.
.LI
\s-1AT&F\s+1 does not change \s-1S24\s+1.
.LE
\s-1S24\s+1 is undocumented and only
available in firmware revision 3507/3506 (V.17) or later.
.LI
Receiving at 4800 baud v.27 does not work correctly; received
data is garbage (this is fixed in firmware revision 3225/3310).
.LI
Commands must not be sent to the modem too fast, no more than
every 50ms (or more) depending on what the modem is doing.
.LI
In some firmware revisions
the modem gets confused by receivers that assert a data
carrier before sending \s-1CED\s+1; a \s-1+FCERROR\s+1
result is returned before
usually returning ``\s-1NO CARRIER\s+1''; this can sometimes be overcome
by sending 1300 Hz \s-1CNG\s+1 tones instead of the normal 1100 Hz tones
.LE
.H 3 "Hayes Optima 24+Fax96 (TR00-J260-001 XXX)"
.BL
.LI
Receiving is unreliable; I was never able to get the receipt
of \s-1TCF\s+1 to work correctly in the short time that I had the modem
(no data was delivered after establishing carrier before timeout).
.LI
See also below under Class 2.
.LE
.H 3 "Nuvo Voyager 96424PFX (AF-C2500-E0)"
.BL
.LI
\s-1RTS/CTS\s+1 flow control is not honored; use software flow control.
.LI
The factory configuration of \s-1&C1\s+1
causes problems; do "\s-1AT&C0&W\s+1" to set
\s-1DCD\s+1 handling before starting the facsimile server.
.LE
.H 3 "Supra v.32bis (V1.200-H TR14-Jxxx-001)"
.BL
.LI
The \s-1+FAE\s+1 command that can be used to enable auto-detect of calls from
data modems is only accepted in Class 0 (data mode); I
h
have never been
able to get it to work correctly (when setup the modem is either unable
to establish carrier, or the modem locks up after notifying the host)
.LI
\s-1RTS/CTS\s+1 flow control is not honored while sending/receiving page data;
use &K4 for software (\s-1XON/XOFF\s+1) flow control.
.LI
See also below under Class 2.
.LE
.H 3 "Twincom 144/DF (V1.270 TR14-Jxxx-001)"
.BL
.LI
\s-1RTS/CTS\s+1 flow control is not honored while sending/receiving page data;
use &K4 for software (\s-1XON/XOFF\s+1) flow control
.LI
See also below under Class 2.
.LE
.H 3 "USRobotics Sportster (Supervisor 4.1, DSP 10)"
.BL
.LI
Timing problems have been observed with older firmware revisions;
if you have problems, be sure to verify the firmware revision.
.LI
When sending, \s-1DCD\s+1 is raised when carrier is first received, but it is
then dropped from the first \s-1HDLC\s+1 receive until the point where the
initial training is sent (from that point on \s-1DCD\s+1 is asserted).
This is a problem under IRIX 4.X systems
because there is no way to override this behaviour in the modem
and IRIX is not capable of ignoring \s-1DCD\s+1 when the modem is
accessed via the character special device files that support \s-1DCD\s+1
and/or \s-1RTS/CTS\s+1 flow control.
.LI
In testing the modem locked up during transmission to a Multi-Tech 1432BA
modem and failed to respond to the host dropping \s-1DTR\s+1.
.LE
.H 2 "Class 2 Modems"
.H 3 "AT&T PARADYNE EDC 3710-A2-203 (C01.66.06)"
.BL
.LI
Result strings for \s-1+FDCC=?\s+1 and \s-1+FDIS=?\s+1
are semantically incorrect;
ranges are returned as (a,b) instead of (a-b); e.g. (0,5) instead
of (0-5) for signalling rate; this causes problems in deducing the
true set of modem capabilities
.LI
The modem sends the host ^S/^Q during page data transmission (\s-1+FDT\s+1)
even when \s-1RTS/CTS\s+1 flow control is enabled.
.LI
Copy quality checking cannot be disabled.
.LI
There is no support for transmission of 2D-encoded data.
.LI
The modem was observed to enter a state where it repeatedly sent
\s-1EOP\s+1 when commanded to send \s-1MPS\s+1
(for \s-1AT+FET=0\s-1); power-cycling the
modem cleared this condition.
.LE
.H 3 "Everexfax 24/96D (911027)"
.BL
.LI
Zero-padding in the EOL codes of received facsimile data is often
not zero when the Phase B+D bit ordering is set to "direct"; a
workaround is to use \s-1+FBOR=2\s+1 and do bit reversal in the host.
.LE
.H 3 "Hayes Optima 24+Fax96 (TR00-J260-001 XXX)"
.BL
.LI
Many commands (e.g. \s-1ATZ\s+1)
generate annoying clicks and pops from the speaker.
.LI
Using ``@;'' in the dialing string causes the modem to return
``\s-1NO ANSWER\s+1'' when calling many modems.
.LI
The modem does not do a good job of holding reliable high speed
carrier\(emwhen sending and receiving, data is frequently corrupted
at both 9600 and 7200 baud (the phone line did not appear
to be the reason as other modems worked fine in back-to-back
testing).
.LE
.H 3 "Multi-Tech MT1432BA (0307)"
.BL
.LI
There are problems communicating with Sharp model 6200 fax machines;
this is reportedly fixed in revision 0309 of the firmware.
.LI
The \s-1EC\s+1 (error correction) subparameter reported in
\s-1+FDIS:\s+1 result strings can contain invalid values (2).
.LE
.H 3 "Practical Peripherals PM14400FXMT (2.17)"
.BL
.LI
Defaulted subparameters in \s-1+FDIS\s+1 and \s-1+FDCC\s+1
commands are wrongly treated as zero.
.LI
\s-1+FDIS\s+1 commands to set session parameters after establishing a
connection with a remote machine are accepted but ignored; this
makes it impossible to select/change data format (\s-11D\s+1 vs
\s-12D\s+1 encoding)
and vertical resolution (98lpi vs 196lpi); since it is not in general
feasible to set all session parameters before dialing the telephone,
this problem makes it possible only to support the minimum set of
Group 3 capabilities (\s-11D\s+1 data, 98 lpi)
.LE
.H 3 "Supra v.32bis (V1.200-H TR14-Jxxx-001)"
\fINote: firmware revision
V1.80-02 TR14-Jxxx-001 is a significant improvement over
previous firmware; it is highly recommended that you upgrade your modem
if you do not have firmware at or near that revision level.\fP
.BL
.LI
Changing \s-1DCD\s+1 handling can cause the modem to drop \s-1DSR\s+1.
If this is done
during initialization the fax server can get confused.
Be sure that the setting loaded from \s-1NVRAM\s+1 on reset agrees with
the value specified in the configuration file (\s-1&C1\s+1 by default).
One possible way of doing this is to specify \s-1&F2\s+1 for
the ModemResetCmds parameter.
.LI
The line counts in the \s-1+FPTS\s+1 result code during a reception are
total nonsense.
The only way to deduce the number of lines in a received page of data
is to parse the data on the host.
.LI
Facsimile reception is locked at 19200 baud.
.LI
Adaptive answer is not reliable (improved in V1.80 firmware).
.LI
The training algorithm can loop forever; client software must
timeout \s-1+FDR\s+1 requests (not observed in V1.80 firmware).
.LI
The firmware has problems retransmitting the post-page response message
(less frequently observed in V1.80 firmware).
.LI
\s-1RTS/CTS\s+1 flow control is not honored while sending/receiving page
data; use \s-1&K4\s+1 for software (\s-1XON/XOFF\s+1) flow control.
.LE
.H 3 "Twincom 144/DF (V1.270 TR14-Jxxx-001)"
.BL
.LI
Changing \s-1DCD\s+1 handling can cause the modem to drop \s-1DSR\s+1.
If this is done during initialization it can cause the fax server to
get confused.
Be sure that the setting loaded from \s-1NVRAM\s+1 on reset agrees with
the value specified in the configuration file (\s-1&C1\s+1 by default).
.LI
Instead of the normal \s-1&D3\s+1 setup string for \s-1RC144AC\s+1-based modems,
\s-1&D2\s+1 should be used (note that this configuration must be done
manually as \f2faxaddmodem\fP is incapable of distinguishing between
\s-1RC144AC\s+1-based modems).
.LI
The line counts in the \s-1+FPTS\s+1 result code during a reception are
total nonsense.
The only way to deduce the number of lines in a
received page of data is to parse the data on the host.
.LI
The modem has frequently been observed to lockup during message
receive (i.e. \s-1+FDR\s+1); it dropped \s-1DCD\s+1
to the host but did not return
<\s-1DLE\s+1><\s-1ETX\s+1> and/or a \s-1+FHNG\s+1 code.
.LE
.H 3 "ZyXEL 1496E (U1496E  V 5.02 M)"
\fINote: firmware revision 6.01 is a significant improvement over
previous firmware revisions
It is highly recommended that you upgrade your modem
if you do not have firmware at or near revision 6.01.\fP
.P
In the following list, items marked
with a \(dg are known to be fixed in the
6.01 revision of the firmware.
.BL
.LI
The \s-1+FMDL?\s+1 and \s-1+FREV?\s+1
commands return the same string, the concatentation of
the modem model and the firmware revision.
.LI
Some prom revisions do not include a trailing ``\s-1OK\s+1''
in response to \s-1+FDCC=?\s+1.\(dg
.LI
\s-1DC2\s+1 must be sent to the modem to trigger the transfer of Phase C
data from the modem to the host after a \s-1+FDR\s+1 command; this reflects
revision 2388-B of the Class 2 spec and is different from the \s-1DC1\s+1
required by 2388-A (and accepted by most modems).
.LI
The modem advertises that it supports the \s-12DMR\s+1 data format, but it
does not; this "advertisement" is both in its result string for a
\s-1+FDCC=?\s+1 query and in the \s-1DIS/DCS\s+1 sent to clients.\(dg
.LI
Sending \s-12DMR\s+1 data to the modem can cause it to lock
up leaving \s-1CTS\s+1
low to the host; some versions of firmware also send an infinite
stream of trash to the remote side when this condition occurs.\(dg
.LI
In some prom revisions the result string from a \s-1+FDCC=?\s+1 query does
not conform to any syntax listed in either 2388-B or 2388-A;
furthermore, it requires a context sensitive parser!\(dg
.LI
\s-1+FDIS\s+1 commands to set session parameters after establishing a
connection with a remote machine are accepted but ignored; this
makes it impossible to select/change data format
(\s-11D\s+1 vs \s-12D\s+1 encoding)
and vertical resolution (98lpi vs 196lpi); since it is not in general
feasible to set all session parameters before dialing the telephone,
this problem makes it possible only to support the minimum set of
Group 3 capabilities (\s-11D\s+1 data, 98 lpi).\(dg
.LI
Sending non-Class 2 commands to the modem after establishing a
connection often causes the modem to drop carrier; for example,
\s-1ATM0\s+1 before a \s-1+FDR\s+1 command will do this.
.LI
The line counts in the \s-1+FPTS\s+1 result code during a reception are
total nonsense.
The only way to deduce the number of lines in a
received page of data is to parse the data on the host.
.LI
In later versions (5.05 for example) the syntax of the \s-1+FPTS:\s+1
result code violates 2388-A and/or 2388-B.
.LI
There is no way to abort a session\(emthe \s-1+FK\s+1 command is not
recognized).
.LI
When sending, the modem appears to immediately drop \s-1DCD\s+1 when it
loses carrier.
This usually occurs after a final \s-1+FPTS\s+1 is sent
to the host, but before the requisite OK and and/or \s-1+FHNG:\s+1 strings.
This action appears to be independent of whether or not \s-1DCD\s+1 is
configured to follow carrier (i.e. &C0 or &C1).\(dg
.LI
When receiving with a negotiated 14400 signalling rate, the \s-1+FDCS:\s+1
status string indicates a 9600 baud signalling rate (br=3).\(dg
.LI
The reception of multiple documents appears to cause the modem to
hangup (i.e. an \s-1EOM\s+1 post page message causes the modem to hangup).\(dg
.LI
The modem sometimes sends received data to the host with the
wrong bit order.\(dg
.LI
The scheme used to do adaptive-answer asserts a data carrier before
falling back to a fax carrier.
This has been observed to confuse a few fax modems, thereby
making it impossible to receive facsimile without disabling adaptive
answer (\s-1+FAA=0\s+1)
.LI
\s-1AT+FLID?\s+1 returns ``\s-1OK\s+1'' but not the
current value of the local identification string.
.LE
.H 2 "Other Modems"
.H 3 "Abaton InterFax 24/96"
.BL
.LI
Abaton 24/96 modems have been observed having
problems communicating with facsimile machines
connected by a lossy or noisy
phone line (e.g. overseas).
.LE