E1 Channel Numbering
An E1 has 32 channels numbered as: 0 1 2 3 4 5.....31 where the zeroth channel is for frame sync.
An E1 can carry data or voice on 31 of 32 channels numbered as: 1..31.
Sangoma wanpipe allows configuration of the 31 usable E1 channels numbered as: 1..31
ss7boost allows configuration of the 31 usable channels numbered as: 0..30
T1 Channel Numbering
A T1 has 24 channel numbered as: 1..24 and all 24 channels are available for voice and signaling.
Sangoma wanpipe allows configuration of all 24 channels numbered as: 1..24
ss7boost allows configuration of all 24 channels numbered as: 0..23
CIC Assignment to Channel Numbers
In ISUP, each timeslot of a E1/T1 in a trunk group has a code assigned to it called a Circuit Identification Code (CIC). The
CIC Mapping procedure is the assignment of CIC to all timeslots in a trunk group.
Each trunk has a CIC base number. This is the CIC assigned to the first usable channel in a trunk. The CIC base number is assigned to Sangoma channel 1 or ss7boost channel 0. The timeslots on a trunk are assigned a contiguous sequence of integer CIC values. There is no requirement for contiguous CIC ranges from one span to next. A CIC value may only be used once between any two SS7 SSP (switching signal points).
Often a telco will assign CIC numbers to the 0th sync. channel and to SS7 link channels even though they are not used for voice. In this case there will be gaps in the CIC ranges of voice channels.