S-registers and escape sequence, Aborting an escape sequence, Appendix i – Multi-Tech Systems MT2834MR6 User Manual

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Appendix

S-Registers and Escape Sequence

There are two S-registers to modify the functioning of escape sequences. Register

S32

establishes a value

for how much time may elapse between the receipt of the beginning of the escape sequence, whether
<BREAK> AT or +++AT, and the receipt of a <CR>. This interval is known as wait-for-<CR>-time, or break
passthrough.

Assign a value in increments of 100 milliseconds to

S32

. The default value is 20, or 2 seconds. In the

+++AT<CR> method, the wait-for-<CR>-time interval begins once the

A

in +++AT is received by the modem.

In the <BREAK> AT method, the wait-for-<CR>-time interval begins once the modem has received the break
signal.

Register

S34

is used in conjunction with in-band escape sequence, +++AT<CR>, to establish the maximum

number of characters the modem can buffer following an AT, before a <CR> must be received. The default
value is 10 characters. Do not confuse this buffer size with the regular command mode buffer length of 60
characters.

Register

S34

does not affect our out-of-band escape sequence’s buffer length, which is fixed at 60

characters.

Aborting an Escape Sequence

The +++AT<CR> escape will abort if you do not issue a <CR> before the wait-for-<CR>-time interval expires.

The <BREAK>AT<CR> method will also abort if you do not issue a <CR> before the wait-for-<CR>-time
interval expires, and also if any of the following occurs:

1.

An illegal sequence is detected, including:

a)

A character other than A follows <BREAK>;

b)

A character other than T follows <BREAK>A;

c)

Two <BREAK>s are received in succession.

2.

The command buffer overflows before a <CR> occurs.

If you have any questions regarding the information in this appendix, please contact Technical Support (see
Chapter 7).

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