Enabling the R2 Protocol

Enabling the R2 Protocol

Using the R2 protocol is similar to using the LEC protocols. Each individual channel is enabled using an L4L3mENABLE_CAS message. When the module receives this message, it will initialize all timers and data structures associated with the specified channel, put the line in idle state “onhook” and respond with an L3L4mCAS_ STATUS message.

The application must select the following signaling type:

l43msg.data.cas_data.signalling_type = IISDNsigtypeR2_ CAS;

This mode operates the inter-register protocol stack on the DSP processors. The iisdn.h file also identifies CAS signaling type IISDNsigtypeR2_MF. This is an IISDN provision for operating R2 signaling on certain controller modules that incorporate modem chips that provide basic MF generation and detection services to IISDN. This capability is not currently released.

For all types of CAS signaling, the lapdid value (zero-based) in the common message header indicates the network interface (line) on the module receiving the message. The call reference value (field call_ref) is a 16-bit value that must have the lapdid value in the most significant 8 bits and the B-channel in the least significant 8 bits (if no B-channel needs to be specified, use 0 for the least significant byte). Since not all BSMI messages involve a B-channel, there is no field in the common message header to specify the B-channel. For some messages the B-channel is specified in the message-specific data structure, and for others the B-channel is inferred from the call reference value. Line and B-channel numbering is 0-based, and the B-channel numbering is line-specific (that is, the first B-channel on the second line is numbered 0).

All of the necessary trunk customization parameters are contained in the IISDN_E1_CAS_R2_DATA portion of the L4L3mENABLE_ CAS structure. It is important that all parameters be filled. Most of the parameters are network specific and cannot be modified without resulting in protocol failure. Others are modifiable according to the requirements of the user's application. Dialogic supplies C header files that specify the parameter settings for certain national variants.

November 2009

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Dialogic 6.2 manual Enabling the R2 Protocol, November 342