I have a strange problem that is driving me nuts.
I am using Asterisk 18.104.22.168 with a Digium B410p ISDN card with the mISDN drivers. I have the everything working however the voice quality presented to the internal sip handset user when the call is to a PSTN connection is poor. The quality presented to the PSTN target is good.
LED on the B410p is red but when a call is active is green.
My ISDN line is in the UK provisioned by BT and is ptmp.
The process that I have followed to get this working is:
Copy the following to the freshly built system:
RPM install the kernel-devel
make && make install of mISDN
make && make install of mISDNuser
make clean && ./configure && make && make install on Asterisk
edit /etc/misdn-init.cfg and /etc/asterisk/misdn.cfg
To make the above take effect I stop * then “/etc/init.d/misdn-init start” then restart *
I add the custom route for mISDN in FreePBX and point an any/any DDI rule to the Aastra 55i handset.
Inbound and outbound calls work but the user on the Aastra 55i hears poor quality from the connected PSTN user. The PSTN user get good quality.
Internet SIP to SIP is also good quality.
Below is what I have already tried to sort this:-
- Tried on two different machines
- updated / down graded mISDN
- tried recompiled kernel with 250 timing
- Tested ISDN line with other kit and its fine
- Tried with Asterisk 1.2 and it was OK but mISDN caused kernel panics
- Everything looks OK within Asterisk
- tried disabling echo cancellation on the b410p
- tried disabling jitterbuffer both in SIP config on Asterisk and on the b410p and combinations of both
What it intend trying next is :-
- Using a Polycom handset
- Down grading the kernel version
Below are the config files for mISDN :-
Does anyone have any ideas ?