SDK: GSM data calls

Owned by Nathaniel Halbrooks
Feb 05, 2024
1 min read

The calltype GSM in the SDK sets the B channel to GSM (V.110) but it does not automatically set the bearer capabilities.

Therefore, when you try and make an outgoing call (using the Simple Data Transfer sample in the SDK, for example), you will get disconnected - DisconnectReason = 12 which translates to "DivaDRUnspecifiedError".

The reason that we do not set the bearer capabilities is that several switches do not like this and do not pass the call.

Therefore, customers should modify the sample and set the bearer capabilities. The bearer capabilities are set by the property DivaCPT_BearerCapabilities. The coding is done first byte length field then the coding. For 9600 it should be (values as hex):

  1. 0x04 0x88 0x90 0x21 0x48

 So, instead of using DivaConnect, the typical sequence in the application would be:

  1. DivaCreateCall DivaSetCallProperties (DivaCPT_CallType = DivaCallTypeGSM) DivaSetCallProperties (DivaCPT_LineDevice = LINEDEV_ALL) DivaSetCallProperties (DivaCPT_BearerCapabilities (length=0x04 data=0x88 0x90 0x21 0x48))

NOTE

A customer in Denmark reported that in his case, he had to set the string to be

  1. 0x06 0x88 0x90 0x21 0x48 0x46 0xBB

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