I am using native sip apis to implement sip calling in android app and it is working fine but in some devices like CANVAS 3 it was not working .After debugging I found this line of code was returning NULL
**manager = SipManager.newInstance(ctx);**
That measns that device does not support Sip Apis.But on the same device other application for sipcalling like SipDroid etc are working properly.How it is possible ?Are they do not use native sip Apis???