Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

ISDN 'Channel IE type'

Can anyone elaborate (or share a doc) on exactly what this does? It is a Call Manager configuration option for Digital Access PRI gateways. The available options are ;

*Timeslot number


*Use number when 1B

*Continous number.

Cisco Employee

Re: ISDN 'Channel IE type'

When the Channel IE type is set as "timeslot" , this specifies the B channel to use for a call as a number. For example, if a Q931 message such as a Restart message refers to B channel 5, the channel IE contains the number 5.

If it is set as "Use number when 1B" , it will specify the B channel to use as a timeslot (discrete number) for any message that refers to a single B channel, but it will summarise all the timeslots as a bit mask to represent all the channels if the mesage refers to multiple B channels.

This bit mask summary is also refered to as a "Slotmap".

Only certain messages (such as Restart) can specify a range of B channels. Normal call control (Setup/disconnect) generally only references a single B channel. In most cases you don't need to alter this setting.

Refer here for more details (from the CCM help page) -

Timeslot Number - B-channel usage always indicates actual timeslot map format (such as 1-15 and 17-31 for E1).

Slotmap - B-channel usage always indicates a slot map format.

Use Number When 1B - Channel usage indicates a channel map for one B-channel but indicates a slot map if more than one B-channel exists.

Continuous Number - Configures a continuous range of slot numbers (1-30) as the E1 logical channel number instead of the noncontinuous actual timeslot number (1-15 and 17-31).

New Member

Re: ISDN 'Channel IE type'