VCM cards are used to provide voice compression channels for calls between IP and non-IP devices, devices being both trunks and extensions. VCM cards with differing numbers of voice compression channels are available.
• For the Small Office Edition control unit, either 3 or 16 voice compression channels with 40ms echo cancellation are pre-built into the module. These cannot be changed.
• For IP500 control units, voice compression channels can be added using either IP400 VCM modules mounted on a IP500 Carrier Card or using IP500 VCM cards.

