User comments

From SIPfoundry sipx, The Open Source SIP PBX for Linux - Calivia

User comments on different ITSPs

The following comments refer to the current development version of the SIP Trunking support for sipXecs. This feature will be released with the sipXecs release 4.0 early 2009. Comments added below will be used in the test effort to improve interoperability prior to release.

Provider (ITSP)	Comments
sipcall.ch
callwithus.com
cbeyond.net
voipuser.org
bandtel.com	An email from a Bandtel rep: "BandTel does not support SIP-X". He might have been referring to release 3.10. Sipxbridge does work with bandtel ( see the settings page )
les.net
bandwidth.com	Random call drops from poor carrier support. Blames large SIP packets from sipX. This problem will occur if you directly route calls to bandwidth.com. If you route your call through sipxbridge, this problem will not occur. Sipxbridge has been tested with bandwidth.com. Check your dial plan and gateway Route settings.
eutelia.it
bt.com
vitelity.net