The channelized NM-2CT1 T1/ ISDN PRI module connects to an external CSU and directly to the network. The channelized E1/ISDN PRI module is available with two E1 ports with balanced or unbalanced interfaces. The channelized E1/ISDN PRI module receives and transmits data bidirectionally at the E1 rate of 2.048 Mbps and provides up to 30 virtual channels per E1 port.