SIP Trunk Compatibility Matrix: ITSP providers

Below is a chart of SIP compatible Internet Telephony Service Provider (ITSP) providers along with their current status as of the latest stable release of Open Paging Server. Refer to historical records for data collected on older versions of Open Paging Server.

Untested: Not yet tested

Status	Meaning
Supported	The provider has listed and/or certified Open Paging Server as compatible and confirmed by independent tests by project contributors. The provider may provide technical support at its discretion.
Working as intended	Independent tests by project contributors have noted the system as working. This does not count as provider endorsement and the provider may not provide technical support.
Working with issues	Minor issues exist that don't effect everyday function or have easy workarounds.
Not working	Does not work or requires hard or major workarounds.
Unsupported	The provider does not support Open Paging Server
Blocked	The provider blocks and does not allow Open Paging Server. Changing the server's user-agent to bypass this may go against the provider's EULA.
Untested	Contributors are unable to independently verify compatibility at this time

This is only a known list of providers. Just because a provider is not listed does not mean it won't work.

The Open Paging Server Project nor its partners or staff does not endorse any provider listed on this page. Listed providers do not inherently sponsor or support the project.

Provider	Status	Notes
8x8	Untested
BulkVS	Working as intended
CallCentric	Working as intended	No early media support between internal extensions: may not hear intercepts
Cooperative Computing Alliance	Untested	TLS Required
CSP Community Phone System	Supported
CSPNet	Supported
Ooma Business	Untested
SIPcord	Working as intended	No early media support: may not hear intercepts
Telnyx	Untested
VoIP.ms	Working as intended	No early media support between internal extensions: may not hear intercepts
Vonage	Untested
Zoho	Untested
Zoom Phone	Untested