Cisco has launched an upgrade to its CallManager IP PBX by enhancing the encryption.

Version 4.1 of CallManager allows Cisco 7940G and 7960G IP phones to encrypt signalling and voice streams over an IP phone call. The company said that this would help organisations using VoIP to protect against IP phone eavesdropping or connection spoofing.

IP phone traffic encryption was first introduced to CallManager 4.0, released in February. But the 4.1 software upgrade extends this encryption support across multiple Cisco VoIP products, such as voice gateways as well as the vendor's Unity Unified Messaging voicemail platform.

Call encryption on Cisco VoIP gateways allows users in remote offices to conduct secure IP phone calls, whereas VoIP encryption was limited to only LAN-based IP phone users in the past. On the Unity platform, encryption can also be added to voice messaging traffic. This encryption can be used to help prevent malicious users from stealing voicemail files off of a corporate Unity server. It can also help prevent interception of voicemail streams as users communicate with a Unity server via a Cisco IP phone.

Also added to CallManager 4.1 is expanded Q.Sig support. First introduced in version 4.0, Q.Sig support allows a Cisco IP PBX to communicate with a legacy PBX via the Q.Sig protocol, a standard for PBX interoperability. Enactments in the new Cisco software allow CallManagers to talk to a wider array of PBXs and translate more features between the platforms, the vendor said.