Siemens TC45 Руководство пользователя - Страница 25

Просмотреть онлайн или скачать pdf Руководство пользователя для Блок управления Siemens TC45. Siemens TC45 36 страниц. Multiplexer user's guide

Multiplexer User's Guide

Confidential / Released

4.3.1 Start-up procedure

The only approach to activate the multiplexer protocol is entering the appropriate AT

command AT+CMUX=0. This enables the multiplexer control channel. The next step is to set

up the multiplexer control channel as described in Chapter 4.3.2.

The multiplexer control channel must be set up as the first channel followed by all other

DLCIs. To do so, a SABM frame (see Chapter 4.2.3) must be sent to the GSM engine.

The module responds either with a UA frame if the DLCI was set up, or with a DM frame if

the DLCI was not set up.

No provision is made for repeating the request if a response is not received.

The state machine requesting the multiplexer control channel DLCI = 0 is the "initiating

station", while the other is called the "responding station".

Customer

µC

A response is not essential for every command – for example, an unsolicited result code

does not require a response.

Customer

µC

(Initiator)

Mux_guide_v06

SABM: P = 1

Address Field = DLCI of channel to be established

UA: F = 1, DLCI is being established

DM: F = 1, not ready, DLCI is not established

Address Field = DLCI of requested channel

UIH:

P = 0, C/R = 1

UIH:

P = 0, C/R = 0

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o b i l e

GSM

engine

GSM engine

(Responder)

30.06.2004