It's "my" system. I'm jack of all trades and administration of the phone system is just one aspect of my role.
We didn't upgrade to V5 because it would've started incurring licence costs for IP endpoints that are not required under V4.2.4 ... but we do have a few SIP licences which we've been using these past erm ... "few" years ...
Until August - when "all of a sudden" any call that comes in gets dropped as soon as it's answered ... resolved that (with the help of our SIP provider) by fixing the compression mode on the SIP trunk to G.711 - they said to disable G729 - unfortunately, this version doesn't seem to allow us to enable/disable specific codecs, just set which one (!) is used ... Anyway, that seems to have sorted the incoming calls...
Now we have an issue of a small number of outgoing calls going silent after pickup - the 3rd party can hear us, but we hear nothing. Following a trace (by our SIP provider) they said we needed to disable ULaw - with a link to a document for a system version later than ours.
Our system is a UK one - with ALaw (AFAIK) - in System/Telephony/Telephony - Companding Law is set to ALaw and ALaw Line - there's no option for Codec preference here.
On the SIP line - Compression mode is set to G.711 ALAW64k - with Use Offerer's Preferred Codec ticked - there's no option to tick/untick codecs or set the order of preference here either... having read a bit about the codec preference, it seems it uses the G.711 ALaw first, then if no joy, flips to using G.711 ULaw .... which I'm assuming is the cause of our issue.
I've got around the issue for now by using a SIP box attached to an analogue port that users can manually select with a shortcode - but it's clearly a short term fix and I need to sort a longer term solution.
I'm quite happy to have separate SIP lines in/out if that helps with conflicting configuration ...
The easy answer is "the box is too old and unsupported" - but I'm a bit loathed to throw away what is by and large a perfectly good system and phones just because something has changed externally....
We didn't upgrade to V5 because it would've started incurring licence costs for IP endpoints that are not required under V4.2.4 ... but we do have a few SIP licences which we've been using these past erm ... "few" years ...
Until August - when "all of a sudden" any call that comes in gets dropped as soon as it's answered ... resolved that (with the help of our SIP provider) by fixing the compression mode on the SIP trunk to G.711 - they said to disable G729 - unfortunately, this version doesn't seem to allow us to enable/disable specific codecs, just set which one (!) is used ... Anyway, that seems to have sorted the incoming calls...
Now we have an issue of a small number of outgoing calls going silent after pickup - the 3rd party can hear us, but we hear nothing. Following a trace (by our SIP provider) they said we needed to disable ULaw - with a link to a document for a system version later than ours.
Our system is a UK one - with ALaw (AFAIK) - in System/Telephony/Telephony - Companding Law is set to ALaw and ALaw Line - there's no option for Codec preference here.
On the SIP line - Compression mode is set to G.711 ALAW64k - with Use Offerer's Preferred Codec ticked - there's no option to tick/untick codecs or set the order of preference here either... having read a bit about the codec preference, it seems it uses the G.711 ALaw first, then if no joy, flips to using G.711 ULaw .... which I'm assuming is the cause of our issue.
I've got around the issue for now by using a SIP box attached to an analogue port that users can manually select with a shortcode - but it's clearly a short term fix and I need to sort a longer term solution.
I'm quite happy to have separate SIP lines in/out if that helps with conflicting configuration ...
The easy answer is "the box is too old and unsupported" - but I'm a bit loathed to throw away what is by and large a perfectly good system and phones just because something has changed externally....