Dialogic 6.2 Manuale Utente

Enabling the R2 Protocol

November 2009

355

This section presents an overview of R2 outbound and inbound call 

setup and tear down. LEC protocols and ISDN use a similar 

mechanism.

Once the trunk is configured, a particular channel that is enabled is 

ready to dial an outbound call or process an inbound call from the 

network. The R2 protocol stack automatically selects a DSP channel 

(Boston channel) to perform the tone detection/generation 

operations. The first B-channel on the first line uses the first DSP 

channel, then each subsequent B-channel selects the next DSP 

channel. 

The first B-channel on the next line selects the DSP channel 

immediately following the DSP channel selected for the last 

B-channel of the previous line, thus ensuring there are no gaps in 

the DSP channel usage caused by different number of timeslots in T1 

and E1 lines.

During call setup - either inbound or outbound - the application 

must not issue any commands to the Tone Generation and Tone 

Detection facilities, as these would interfere with the R2 signaling 

and cause the call to be abnormally terminated. If the application 

connecting DSP channels and B-channels through the Telephony 

Bus (H.100), it must ensure the appropriate DSP channel is free and 

connected to the corresponding B-channel when it is ready to 

receive/place calls. Once the call is connected, the DSP and 

B-channels are remapped.