Siemens Mux_guide_v06 manual Customer GSM engine µC, At+Cmux

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Multiplexer User's Guide

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4.4Example: Establishing logical channels without parameter negotiation

•Send AT+CMUX=0; wait for the response

•Send Request SABM for DLCI = 0; wait for the response

•Send Request SABM for all requested DLCIs; wait for the response

As a result the multiplexer is established and information / data can be transmitted (⇒ ready for Information Transfer).

		Serial
		interface
	Customer	GSM engine µC
	µC	GSM engine µC
	µC
	Closed Down	Closed Down
	RequestStartUp	IndicationStartUp	Start Up	"AT+CMUX"
		IndicationStartUp
	ConfirmStartUp	ResponseStartUp
	ConfirmStartUp
	Disconnected	Disconnected
	Disconnected	Disconnected
	DLCI = 0	DLCI = 0
	RequestSABM	IndicationSABM	DLC Establishment,	Create DLCI = 0
	DLCI = 0	IndicationSABM
	DLCI = 0	DLCI = 0
		DLCI = 0
	ConfirmUA	ResponseUA
	ConfirmUA	DLCI = 0
	DLCI = 0

	Connected	Connected
	DLCI = 0	DLCI = 0
	Disconnected	Disconnected
	DLCI = 1	DLCI = 1
	RequestSABM	IndicationSABM	DLC Establishment,	Create DLCI = 1
	DLCI = 1	IndicationSABM
	DLCI = 1	DLCI = 1
		DLCI = 1
	ConfirmUA	ResponseUA
	ConfirmUA	DLCI = 1
	DLCI = 1

	Connected	Connected
	DLCI = 1	DLCI = 1

Figure 13: Establishing the multiplexer control channel and the logical channel

Mux_guide_v06

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30.06.2004

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Contents Version DocID Muxguidev06 Siemens Cellular EnginesDocument Name Multiplexer Users Guide Multiplexer Users GuideJune 30 Muxguidev06Contents Tables Multiplexer protocol version controlChapter What is new Document historyIntroduction Supported products and related documents ReferencesTerm and abbreviations Abbreviation DescriptionMultiplexer protocol an overview Product concept and architectureVirtual channels and AT commands Characteristics Integrating multiplexer into the customer applicationBasic requirements RestrictionsFunctions without channel dependencies Timing conditions Multiplexer control and signaling lines Flow controlLogical flow control RTS/CTS on the physical channelsRTS/CTS on the logical channels COM M COM N COM P RTS/CTSEscape sequence Power savingBandwidth of logical channels Data link layer Structure of the multiplexer protocolIntroduction of the multiplexer protocol Flag sequence Address fieldControl field Frame TypeLength indicator Information fieldFrame checking sequence field FCS BitState diagrams Relationship between the customer µC and the GSM engine µC Serial Interface Customer GSM engine AT+CMUXSerial interface Customer µCCustomer EngineGSM engine ResponderClose-down procedure DLC releaseMultiplexer control channel Type fieldLength field Test command TestMultiplexer close down CLD Modem status command MSC Break signal optional Bit Not supported Power saving control PSC Commands Bit DescriptionType Bit Value octet Length=1 BitNon-supported command response NSC Value octet Bit Command TypeNon-supported command No Value octet Length=0Customer GSM engine µC AT+CMUXMultiplexer protocol version control IntroductionModem status command MSC Signals Break Signals Octet Optional Command BitSignals Bit Multiplexer protocol versionsTroubleshooting Implementing version controlCoding of TestCommand message Example of TestCommand message