[time-nuts] TimeSource 2500

Dennis Ferguson dennis.c.ferguson at gmail.com
Sat Nov 24 02:08:34 UTC 2018


> On Nov 23, 2018, at 02:54, Dmitry Khorkin <ekaninchen at gmail.com> wrote:
> 
> For RS232 (Tx pin) character duration is about 104 usec, which corresponds
> to 9600 bps.
> Information it sends is: "ATE0&R1&C1S0=1", every 6 seconds. Though if i
> echo something, it stops for 62 seconds and then repeats spamming with 6
> sec period.
> E0   = turn off echo
> &R1 = &R - RTS/CTS option; &R1 - Ignore CTS from DTE (always send)
> &C1 = &C - Data Carrier detect option; &C1 - DCD follows carrier state
> S0=1 - 1 ring before auto answer

Ah, the port is configured to talk to a modem and, given the S0=1 part,
there is a good chance it expects the modem to be a dial-in that answers
calls.

It has been a long time since I had to deal with one of those but the
response it is expecting to the command it sent is very likely

    \r\nOK\r\n

where \r is carriage return (== control-M) and \n is linefeed/newline
(== control-J). Replying with that should get you past the command it
is now sending to see what it does next.

If it really expects a dial-in modem you may need to manipulate
control signals enough to convince the TS2500 that the “modem” has
connected a call before you’ll ever see a command interpreter or
anything. The minimal protocol will have the TS2500 assert DTR when
it is ready for the modem to answer a call and deassert DTR when it
wants the modem to hang up the phone. The modem, having seen DTR
asserted, will assert DCD when a call has been connected and
deassert DCD when the call hangs up. DCD should probably start
off deasserted and remain so until after you’ve acknowledged the
modem configuration string.

If you ever do get to a command interpreter a priority should be
to find the configuration that makes it think there’s a modem
attached and reset that to a hardwired line.

Dennis Ferguson



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