STAC VIP and VH2, more so than previous Comrex products, rely on the ability to interwork with some type of established VoIP service.

This service may be delivered via:

• SIP-based IP PBX
• POTS or T1 hardware gateway device
• Cloud-based telephone service provider

Each of these services can be quite complex. In a perfect world, the architecture of each of these services would be perfectly standardized, and it would be a simple thing for STAC VIP and VH2 to be programmed to interwork with each of them.

We find this not to be the case, however, and while Comrex is committed to STAC VIP and VH2 being as universally compatible as possible, limits to this commitment do exist.

Below is a list of the PBXs, Gateways, and service providers that we have knowledge of being used successfully with STAC VIP and VH2. This is not meant to imply complete compatibility-in most cases we’ve only heard a brief amount of feedback from a customer claiming success. In some cases we’ve engineered the compatible mode ourselves, with customer help. In all cases, firmware updates or other changes to the service can cause subsequent compatibility issues.

It is our hope that STAC VIP and VH2 customers who intend to use the product on services other than those noted will contact our support team before buying their system. We can do a quick analysis of the proposed service and give some hints as to whether we expect smooth sailing, small bumps, or large roadblocks in the project. Comrex has tested our IP telephone products on many major brands of Providers, PBXs, and gateways and has engineered support for most. Note that even basic interoperability testing requires that our support team has access to the Comrex device via SSH. If your network can not accomodate this, we can not support interoperability efforts at all.

The world of VoIP, is, however, a complicated one and our resources prevent us from establishing compatibility with every existing service, device, and firmware version. For this reason we can not guarantee compatibility. If you have difficulty interworking your Comrex gear with your Provider, PBX, or gateway, please contact Comrex support for ideas or workarounds. Short of this, we can only offer that you return the product for a refund if compatibility can not be established.

• Onsip
• CallCentric
• BroadVoice
• Crexendo
• Frontier VoIP (configure as a “SIP Trunk” in STAC VIP)
• Sip2SIP
• Vocalocity
• Nextiva
• Vonage Business

• Grandstream GXW4004 * Preferred gateways *
• Patton Smartnode 4114/4312

• Asterisk
• Freeswitch
• Cisco CUCM
• 3Com NBX
• Toshiba CIX100/CIX670

List updated July, 2017