System information

signalling = pri_cpe
channel => 1-23
Some carriers will use Nortel’s DMS switch, which commonly uses the DMS100 pro-
tocol instead of National ISDN 2. In this case you would set the switchtype to DMS100:
switchtype = dms100
Outside of Canada and the US, PRI circuits will be carried on an E1 circuit.
In Europe, an E1 circuit used for PRI will normally have the following characteristics:
• Line code: CCS
• Framing: HDB3 (high-density bipolar)
The /etc/dahdi/system.conf file might look something like this:
span = 1,0,0,ccs,hdb3,crc4
bchan = 1-15,17-31
hardhdlc = 16
And the /etc/asterisk/chan_dahdi.conf file should look something like this:
[trunkgroups]
[channels]
usecallerid = yes
hidecallerid = no
callwaiting = yes
usecallingpres = yes
callwaitingcallerid = yes
threewaycalling = yes
transfer = yes
canpark = yes
cancallforward = yes
callreturn = yes
echocancel = yes
echocancelwhenbridged = yes
relaxdtmf = yes
rxgain = 0.0
txgain = 0.0
group = 1
callgroup = 1
pickupgroup = 1
immediate = no
switchtype = qsig
context = pri_incoming
group = 0
signalling = pri_cpe
channel => 1-15,17-31
Basic Rate Interface ISDN (commonly known as BRI, or sometimes even just
ISDN) was intended to be the smaller sibling to PRI. BRI only provides two 64K
B-channels and a 16K D-channel. The use of BRI has been somewhat limited in North
BRI ISDN.
140 | Chapter 7: Outside Connectivity