User manual

2-14 AT COMMANDS: DATA MODEM

&X – Setting the Clock Signal in Synchronous Mode

The &X command determines down how the Clock Signal is produced.

AT&X0 The modem produces its own send-pulse (factory setting)

AT&X1 The modem awaits the send-pulse from the computer

AT&X2 The modem produces the send-pulse from the pulse which it re-

ceives (pulse loop). This command must not be active simultane-

ously with two connected modems.

&Y – Selecting a Start Conﬁguration

The &Yn command is used to determine which of the non-volatile stored proﬁles

(&W command) will be active when the unit is switched on. The n parameter (n =

0, 1) is used to select the proﬁle required (factory setting is 0).

&Z – Telephone Number Storage

The modem can store up to 20 telephone numbers by using the AT&Zn=x com-

mand (n = 0-19). These can be dialled automatically by the command ATDS=n.

Telephone numbers must not be more than 40 characters in length (digits + dial-

ling parameters).

For example: AT&Z7=P06897 123456

The telephone number P (for pulse dialling) 06897 123456 is stored in memory 7.

\A – Maximum MNP Block Size

The \A command determines the maximum size of the data blocks for MNP4 and

MNP5 connections but not for MNP1-3. Where good telephone lines exist, large

data blocks will speed transmission, because the quantity of additional bits is less.

With poor telephone lines it is more sensible to transmit small data blocks as if

there is an error, the entire data block will have to be sent again.

AT\A0 Maximum block size is 64 bytes

AT\A1 Maximum block size is 128 bytes

AT\A2 Maximum block size is 192 bytes

AT\A3 Maximum block size is 256 bytes (factory setting)

\B – Sending a Break Signal

The \B command is used to send a Break signal to the remote modem (see \K com-

mand).

In order to enter the \B command, you must ﬁrst return from the existing data

connection to the Command mode, using the Esc sequence. The Break signal is

ﬁxed at 300 ms.