isdn30 vs isdn30e

[PappaG]

Hi all

you will have to forgive me as i dont know a great deal about isdn. We have an issue with calls not dropping using an ip softphone to control the pstn network. The call flow would be call delivered from exchange to customer PBX, customer PBX then generates call to remote office and connects inbound call to PBX to remote office worker. If remote office worker terminates the call it takes 1m30s or 2mins depending if the inboud call from the exchange to the PBX origonated from a mobile or a standard phone line. In this example problem persists when remote office is using ISDN30. We have converted these sites to ISDN30e and in the same scenario the call release is instant. Can anyone explain the massiging difference that causes this as the ISDN30e remote offices work correctly with the call release between the PBX and remote office. The scenario above is how we test it as this delayed release is consistant with the fault.

 

[PeterHurst]

Basically ISDN30 and 30e use different signalling protocols. Both in theory use Q931 but ISDN30e uses the newer ETSI specific Q931 signalling. In general they are the same but they differ in some important areas and from memory you may have hit one - call setup and call clear packets can and often do contain extra fields on ETSI. If you're saying the problem is with the plain ISDN30 it may be that your equipment is ETSI compliant and is either a) expecting the fields to be there and they aren't or b) generating extended fieilds which the exchange doesn't understand.
b) is the more likely - I would ask both your ISDN supplier and equipment supplier to consider this and probably yuou'll need a consultant to come and do a signalling trace. Usually the supplier can do it though they don't always understand the results.