Dialogic 6.2 Manuale Utente

Enabling the R2 Protocol

November 2009

342

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.