IPC - Inter Processor Communication

Multiplexing mode +CMUX

+CMUX

Modules

All products

Attributes

Syntax

PIN required

Settings saved

Can be aborted

Response time

Error reference

partial

No

No

No

-

+CME Error

Description

Enables the multiplexing protocol control channel as defined in 3GPP TS 27.010 [10]. The command sets the parameters for the control channel. The result code is returned using the old interface speed. The parameters become active only after sending the OK result code.

The usage of +CMUX set command during the multiplexing is not allowed.

The multiplexer configuration is as follows:

Table 2. Multiplexer configuration
ModulesControl channelAT commands / data connectionGNSS tunnelingSIM Access Profile (SAP)

LEXI-R10

Channel 0

Channel 1 - 3

SARA-R10

Channel 0

Channel 1 - 3

Syntax

TypeSyntaxResponseExample

Set

AT+CMUX=<mode>[,<subset>[,<port_speed>[,<N1>[,<T1>[,<N2>[,<T2>[,<T3>[,<k>]]]]]]]

OK

AT+CMUX=0,0,,1500,50,3,90

OK

Read

AT+CMUX?

+CMUX: <mode>,[<subset>],<port_speed>,<N1>,<T1>,<N2>,<T2>,<T3>[,<k>]

OK

+CMUX: 0,0,0,1500,253,3,254,0,0

OK

Test

AT+CMUX=?

+CMUX: (list of supported <mode>s),(list of supported <subset>s),(list of supported <port_speed>s),(list of supported <N1>s),(list of supported <T1>s),(list of supported <N2>s),(list of supported <T2>s),(list of supported <T3>s),(list of supported <k>s)

OK

+CMUX: (0),(0),,(1-1509),(1-255),(0-5),(2-255),,

OK

Defined values

ParameterTypeDescription

<mode>

Number

Multiplexer transparency mechanism:

  • 0: basic option

<subset>

Number

The way in which the multiplexer control channel is set up:

  • 0 (default value): UIH frames used only

<port_speed>

Number

Value is ignored.

<N1>

Number

Maximum frame size. The range is 1-1509 and the default value is 31.

<T1>

Number

Value is ignored.

<N2>

Number

Value is ignored.

<T2>

Number

Value is ignored.

<T3>

Number

Value is ignored.

<k>

Number

Value is ignored.

Notes

  • If the multiplexer protocol is not started (the +CMUX set command has not been issued or returned an error result code) and AT+CMEE is set to 2, the +CMUX read command returns the following error result code: +CME ERROR: operation not allowed.

  • For complete compatibility between u-blox products, leave the unsupported/unused parameters blank (which are reported as blank by the +CMUX test command).

  • <T1> must be lower than or equal to <T2>.

  • The multiplexer protocol is supported only on MAIN UART.

  • Each MUX channel configuration stored with AT&W to the personal profile is re-applied everytime the MUX protocol is established.

  • If +USIO configuration is changed, the MUX channels profiles become invalid and shall be restored. For more details, see +USIO notes.

  • GNSS tunneling is not supported.

  • For the configuration of the module power saving during a multiplexer protocol session, see the +UDCONF=201 AT command description.

Last updated: Jan 13, 2025
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