User manual

2-12 AT COMMANDS: DATA MODEM

AT&Q5 The modem attempts to create a data link with Error correction.

You can also specify in Register S36 whether the modem should

go off-line or create an asynchronous link, if this is unsuccessful.

AT&Q6 Asynchronous operation in “Normal” mode. (factory setting)

&R – Control Lines S2 and M2

In asynchronous operation (see also &M0 command), the M2 control line (106/

CTS) is always set up, whether in command mode or in data mode. Where syn-

chronous operation is involved (&M1 to &M3), the following commands apply:

AT&R0 M2 (106/CTS) follows S2 (106/RTS). Where S2 changes over

from On to Off, M2 switches on after the period of time speciﬁed

in the S26 Register. In the M2-OFF status, any data received is ig-

nored.

AT&R1 The modem ignores S2 (the assumption is that S2 is on, so that M2

is also on) (factory setting)

&S – Control Line M1 (107/DSR)

With the &S0 command, the M1 control line is always set up when the modem is

switched on. The effect of the &S1 command (factory setting) is to retain the M1

(DSR) in accordance with CCITT recommendations V.22bis/V.22.

&T – Modem Test Functions

A number of diagnosis commands are available, to enable you to limit any com-

munication problems. These can be entered only when the system is in Command

mode (or in Esc command mode for remote test loops). To use them, the following

procedures must be carried out: -

• Set the communications software to 9600 bps

• Send the command AT\N1 F8 to the modem

➮ In order to disengage the local or remote digital test loops, a telephone con-

nection must ﬁrst be created, from which you can use the Esc sequence to go

into the Esc command mode

AT&T0 End the current test loop and issue an Error report

AT&T1 Start a local, analogue test loop in order to check the computer/

modem and modem/computer links. During this process, the in-

puts from your keyboard should be correctly displayed on the

screen.

AT&T3 Start a local, digital test loop, in which any data transmitted by a

remote modem is returned to it.

AT&T4 Authorise a remote digital test loop for the remote modem (factory

setting)

AT&T5 Stop the remote digital test loop