3Com Courier, Reference

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16-8 C
HAPTER
16: D
EDICATED
/L
EASED
L
INE AND SYNCHRONOUS APPLICATIONS
Synchronou
Dialing Using AT
Commands
To use AT commands to dial, you must set the modem to enter online
synchronous mode after you dial. Then, you dial the remote device’s
number using AT commands. Once the remote device answers, the
modem switches to synchronous mode and starts sending synchronous
timing signals to your computer.
Because the modem will not accept commands when it is in synchronous
mode, you must configure it in asynchronous mode before connecting t
a synchronous network.
The Courier V.Everything modem always generates the Transmit
clock-timing signals when in synchronous mode.
Data Terminal Ready (DTR) override must be OFF when using modem in
online synchronous mode. Use &D1 or &D2. See Chapter 8, Controllin
EIA-232 Signaling
Configuring th
Courier V.Everything
Modem
1 If your communications software isn't running, load the program and
start Terminal mode (see your software user’s guide for instructions).
2 Send
AT&F0B0&X0
to the modem.
The device you are calling should also be set to the equivalent of B0,
which tells the modem to use the V.25 answer sequence, and &X0, which
identifies the modem as the source of synchronous timing signals.
3 Set the connection rate to be used (between your modem and the
remote communications device) when the modem is online.
First try a variable connection rate of &N0. If that doesn't work, try a fixed
connection rate of &N6 (9600 bps) or &N3 (2400 bps)
■
If your modem is set to a fixed rate, and the remote device is not set to the
same rate, the
Courier V.Everything mode
hangs up.
■
Your modem cannot connect at 21.6 Kbps in synchronous mode.
■
This modem does not support synchronous communications under HST,
V.FC, x2, and V.90 modulations.
4 Your modem is able to automatically answer calls.