ZyXEL Communications 2864 - Manual (Page 130)

11–2
Half-Duplex Operation
For a half-duplex modem, the carrier only exists in one direction at any specific
time. The carrier, the local CTS signal, and the remote CD signal will follow the
RTS signal in a certain manner. Some communication software packages written
for half-duplex modems rely on these RTS, CTS and CD signals. For a full-duplex
modem, carriers are always present in both directions. In order for it to simulate a
half-duplex modem, the V.13 protocol is provided where the local CD signal fol-
lows the remote modem's RTS signal. Set
S44.5=1 to enable V.13.
Mode Options
For synchronous data communication, there are two options you can choose from
to define how the modem will operate in the command state.
You can always use the panel operation to control and configure the modem and
use the manual dial and answer to operate the modem.
Dial from Synchronous Mode
1) Dial from the terminal using asynchronous commands.
Set &M1 and use asynchronous AT commands to dial the number. Once the
modem is connected, the modem will enter synchronous operation.
2) Dial through the computer using V.25bis commands.
Some communication software packages on synchronous computers can dial
using V.25bis synchronous commands. In this case, set
&M3 and *I1 and the
modem will accept V.25bis commands and make a synchronous connection.
3) Using DTR to dial a stored number in synchronous mode.
Store the telephone number from the front panel STORE NUMBER menu or by
the asynchronous command &Zn= . Use the DEFAULT DIAL parameter menu or
*Dn command to select the default dial pointer. Set &D1 and either &M1 or
&M3 , then raise DTR from your terminal or communication software. The
modem will dial the default stored number. After the modem is connected, the
modem will enter synchronous operation.
On the model with a DATA/VOICE switch, with S35b4 set, pressing the DATA/
VOICE switch will also cause dialing of the default number.
SYNC DATA AT&M1 The modem accepts asynchronous command
in command state, but exchanges data syn-
chronously in data state.
SYNC AT&M3 The modem accepts synchronous command
(V.25bis) and exchanges data synchronously
with a remote modem.