Paul Christidis wrote:
>
>I'm trying to send an initialization string to a modem and I get the
>following error:
>
><SYS>:file a;dev=116
><SYS>:fcopy from=$stdin;to=*a
>HP31900A.05.02 FILE COPIER (C) HEWLETT-PACKARD CO. 1990
>
>*106*CAN'T OPEN TOFILE
>
>DISPLAY FILE INFORMATION (Y OR N) ?y
>INSUFFICIENT SYSTEM RESOURCES  (FSERR 68)
>
>+-F-I-L-E---I-N-F-O-R-M-A-T-I-O-N---D-I-S-P-L-A-Y+
>!  ERROR NUMBER: 68    RESIDUE: 0                !
>!  BLOCK NUMBER: 262915       NUMREC: 790        !
>+------------------------------------------------+
>0 RECORDS PROCESSED *** 1 ERROR
 
Your port isn't hung.  This is the "correct" response when trying to
FOPEN a modem port where the modem isn't holding Data-Carrier-Detect
(DCD on DTC pin 4) and Data-Set-Ready (DSR on pin 20) high.
 
I believe hung/broken ports more often report FSERR 32, Software
Abort.
 
The old solution was to either configure the modem to hold these
signals high or to use a special cable, tying pins 4 and 20 back to
pin 6, the DTC's Data-Terminal-Ready lead.  Neither solution would
allow the DTC to see line drops however, while the second case would
at least allow the DTC to drop the line (FCLOSE causes DTR to drop.)
 
Newer modems provide for the DSR signal to be set high _most_ of the
time, only dropping momentarily (pulsing) when the modem goes offline.
If you set your modem to have DCD held high all of the time and DSR in
pulse mode, you should be able to communicate with the modem easily.
 
Additionally, it helps if you can setup the modem to do a full reset
upon loss of DTR from the DTC.  This helps get things back to a known
state without having to manually reset the modem.
 
The corresponding settings for many modems are: AT &C0 &S2 &D3.  These
set DCD high, DSR pulsed and reset on DTR loss, respectively.  For US
Robotics Courier modems, the &D3 changes to &D2 and S13=1.  Typically,
you would also issue an AT&W to save the configuration in non-volatile
memory.  Some modems provide storage for multiple configurations.
With these, you'll have to specify the location you're storing into as
well as the location the modem should use upon reset.  Read your modem
manual to verify the specifics for your modem.
 
With the DTR reset option, it's even possible for you to use two
different configurations on the modem, one for incoming calls (the
permanent, stored configuration) and another one for dialing out.  The
dialout program can send a new, temporary, configuration sequence in
front of the dial command, secure in the knowledge that the modem will
revert to its stored configuration once the program stops and DTR
drops.
 
--
------------
Randy Medd
Telamon, Inc.