The Voice/Fax network modules for the Cisco 2600/3600 series enable voice and fax traffic to be routed over either an IP or Frame Relay network. The Voice/Fax network modules slide into the 2600/3600 series network module slots and support either one or two voice interface card (VIC) slots. The VICs are daughter cards that slide into the Voice/Fax network modules and provide the interface to the telephony equipment. Just as the Cisco WAN interface cards (WIC) can be swapped with other WICs, the Cisco VICs can be deployed interchangeably with other VICs.