"NO CARRIER" modem problem

[JPD20]

Hi all,

We're currently developing a project on a Symbol PDT 8100 scanner which should communicate with the host using modems (internal for host, external
for the 8100). It however refuses to communicate with the host. A connection is made, but somehow one of both sides (I think the terminal) hangs up, leaving
me with this kind of LOG file:

2003/03/24 13:11:00.02 >~ .. [RC]RING[RC]
2003/03/24 13:11:04.93 >~ .. [RC]RING[RC]
2003/03/24 13:11:04.94 CM .. MD|ATA
2003/03/24 13:11:04.95 > .. [RC]RING[RC]
2003/03/24 13:11:04.95 << .. ATA[13]
2003/03/24 13:11:06.99 >> .. NO CARRIER
2003/03/24 13:11:06.99 OK .. **; Answering incomming call: <NO
CARRIER>

Timeout settings are sky high and I tried tweaking every modem setting I could find on both host and 8100 side. Are there any modem settings I should change? Any advice would be highly appreciated.

Best wishes,

Joris van Oss

 

[pansophic]

It is hard to tell without more accurate serial data collection, but it appears that you are sending the ATA command twice. Generally, I opt for a simpler design in answering a telephone call, and just set the S0 register to answer on the number of rings that I desire. If any characters are transmitted from the dialing or receiving modem during handshaking, the modem will drop the connection with a NO CARRIER response.

I am not sure what the [] bracketed characters are supposed to mean in this log, but on the second ATA line &quot;ATA[13]&quot; would indicate that it is &quot;ATA<cr>&quot; immediately followed by NO CARRIER.

If you continue to have problems, try setting S0 to 2, Echo off and Quiet on for the receiving modem:

AT S0=2E0Q1<cr>

or as part of your init string. That should suppress the RING messages and automatically answer the call from the scanner.
pansophic