Device Compatibility

with various Telephony Systems products support analog and VoIP phone service. When the phones being used can be purchased from any local retailer, then an analog Whozz Calling? unit is compatible. When VoIP phones are used, a Vertex "Caller ID for VoIP" device is required.


Telephone service companies install many types of digital-to-analog conversion equipment that provides analog lines for customers to use simple, off-the-shelf phones, or connect to legacy phone systems.

Whozz Calling? Compatibility
Standard Local Loop Phone Lines Basic or Deluxe
Digital Cable w/ analog converter Basic or Deluxe
Fiber-optic to analog converter Basic or Deluxe
T1 w/ analog converter Basic or Deluxe
VoIP w/ analog terminal adapter (ATA)
servicing all analog phones
Basic or Deluxe
VoIP w/ analog terminal adapter (ATA)
in same ring group as VoIP phones
Basic units only
Analog extensions cards on a PBX Basic units only
Digital or hybrid extensions on a PBX Not Compatible
ISDN PRI, T1, or Fiber direct to PBX Not Compatible

Voice-over-Internet Protocol (VoIP) service is categorized as Hosted (Cloud Based) or Managed. With Hosted systems, all signaling, switching, auto attendant, and voicemail is accomplished in the cloud - you just connect the VoIP phones. Managed systems have on-premise, programmed equipment responsible for all phone related features.

Vertex units are compatible with any Hosted service using un-encrypted SIP (Session Initiation Protocol) signaling. Vertex units are compatible with most Managed VoIP systems using SIP signaling on the premise.

Vertex Compatibility
Hosted VoIP (unencrypted SIP) Compatible
Hosted VoIP (encrypted) Not Compatible
Managed VoIP w/ SIP Trunk Compatible
Managed VoIP (ISDN or T1 Trunk) w/ SIP Extensions Contact
Managed VoIP w/ other configuration Contact