SIP and H.323 Protocol

The VVX 500/501, 600/601, and 1500 phones can support both SIP and H.

323 signaling simultaneously, and the phones support bridging both types of calls during multi-party conference calls. The phone can automatically detect the correct or optimal signaling protocol when dialing a call from the contact directory or the corporate directory.

While SIP supports server redundancy and several transport options, only a single configured H.323 gatekeeper address per phone is supported. The phone does not require H.323 gatekeepers, but you can use them if available. If an H.323 gatekeeper is not configured or is unavailable, you can still enable the phones to make H.323 calls.

Support of the SIP protocol for telephony signaling can be disabled on the VVX 500/501, 600/601, and 1500 such that all calls route via the H.323 protocol.