The card you are looking for could be the one- or two-port T1/E1 Multiflex Voice/WAN Interface Cards (VWICs) in the High Density Voice Network Module (NM-HDV)' .
In Cisco IOS. Software Release 12.0(7)T, NM-HDV was introduced to support voice connectivity on T1/E1 interfaces from Cisco 2600/3600 series IOS gateways to a PBX or the Public Switched Telephone Network (PSTN). Signaling support on digital and analog interfaces on the Cisco 2600/3600 series gateways now includes BRI, Foreign Exchange Office (FXO)
The above statement is justified in the document given below:
Understanding Support for Voice and Data on 2600/3600 Series Routers
http://www.cisco.com/en/US/customer/products/hw/modules/ps2797/products_tech_note09186a0080100688.shtml
For more information on the NM-HDV module, refer to the following documents:
* Data Sheet: Digital T1/E1 Packet Voice Trunk Network Module
http://www.cisco.com/en/US/customer/products/hw/routers/ps259/products_data_sheet09186a00800921cc.html
* Understanding High Density Voice Network Modules
http://www.cisco.com/en/US/customer/products/hw/modules/ps2797/products_tech_note09186a00800b65d6.shtml
For more information on the Multiflex VWICs, refer to the following documents:
* Data Sheet: Cisco One and Two Port T1/E1 Multiflex Voice/WAN Interface Cards
http://www.cisco.com/en/US/customer/products/hw/routers/ps274/products_data_sheet09186a0080091b9c.html
* Understanding 1 and 2 Port T1 Multi-Flex Trunk Voice/WAN Interface Cards (VWICs)
http://www.cisco.com/en/US/customer/products/hw/routers/ps274/products_tech_note09186a00800aded4.shtml
* Understanding 1 and 2 Port E1 Multi-Flex Trunk Voice/WAN Interface Cards (VWICs
http://www.cisco.com/en/US/customer/products/hw/routers/ps274/products_tech_note09186a00800b6e0f.shtml
