Product Description:
Cisco 2600, 2600XM, 2800, 3600, 3700, 3800 Series -
Dual-Port 48 channel T1 Voice / Fax
Network Module.
About the Cisco 3600 Series:
"Modular high-density router for dial-access or router-to-router
traffic. Supports ISDN, serial, channelized T1, digital modems,
and ATM links. Also supports voice/fax and Frame Relay" (Cisco A Beginner's
Guide Third Edition by Velte & Velte).
About the Cisco 3700 Series:
"Modular routers, targeted at branch offices. Supports Frame
Relay, ISDN, LL, X.25, ATM, fractional T1/E1, xDSL, T3/E3, HSSI
WAN protocols" (Cisco A Beginner's Guide Third Edition by Velte & Velte).