The following is got from www.cisco.com Table 18-258: Platform Maximum T1 Voice Interfaces Supported 2600 Chassis Network Module slot 3620 Chassis Network Module slots 3640 Chassis Network Module slots 3660 Chassis Network Module slots Maximum Number of T1 Voice Ports Supported (max. number of voice channels supported) Two T1 (48 voice channels)-->2600 Two T1 (48 voice channels)-->3620 Five T1 (120 voice channels)-->3640 Twelve T1 (288 voice channels)-->3660 but i want to get info about using E1 card ,e.g. VWIC-1MFT-E1,VWIC-2MFT-E1-DI. For example ,i want to know if 120 channels is also the maxmium limit for using E1 card on a 3640,that is a 3640 can support 5 T1,or 4 E1.Is this conclusion right? Thanks , Frank _________________________________ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]