VoIP Compatibility Issues with Phone Systems


Automated phone systems may encounter problems detecting dialtone for outbound calls, incoming ring, or caller-hangup, when using it on a VoIP line.

There are known compatibility issues with certain VoIP adapters when using the following equipment...

You need to have a compatible VoIP adapter

If you have problems finding an available line to make outbound calls, or dropping calls during a conversation, it is not the fault of your automated equipment. Your VoIP adapter may not be using the standard 48 Volts DC. The Linksys adapter, for example, has a slightly lower voltage.

In some cases, inbound calls are not detected with the Linksys adapter. Linksys uses the European 25 Hz ringing signal at 60 VAC, which may not be detected. Some other adapters are also known to have similar issues.

Known Compatible VoIP Adapters

We have had success with several adapters that are known to be compatible. These ring with the normal 20 Hz signal at 60 VAC, so inbound calls will be detected. They also provide the standard 48 Volts DC on idle lines, so an available outside line will be properly detected.

The following is a list of adapters that were tested and passed...

Solution for users of Vonage®

Make sure you have the new Vonage® V-Portal™ Phone Adapter (Model VDV21-VD). This has been personnally tested by us and found to be compatible with the VoicePro.

Solution for users of Cablevision Optonline®

Make sure you have the Motorola SBV5120 broadband modem. This has been personnally tested by us and found to be compatible with the VoicePro.

Solution for users of D-Link®

The D-Link Model DVG-2001S VoIP Adapter has been reported to work with the VoicePro.

Software Programming Solutions

  1. If you have trouble detecting incoming calls, ask your VoIP provider if they can program their adapter to provide a normal 20 Hz ring signal.
  2. If you have trouble seizing an outside line to make calls, ask if they can set it to provide 48 Volts DC.