The astonishing versatility of the Cisco 2600, 3600 and 3700 router series is highlighted by its broad support of Integrated Services Digital Network Primary Rate Interface (ISDN PRI) connectivity.
The available Cisco 2600/3600/3700 PRI network modules provide various port densities to meet customer requirements at various price points. The optional, integrated CSU lets customers consolidate customer premises equipment (CPE) to provide multifunction dial access server, router, and other capabilities within the Cisco 2600/3600/3700 series in power branch office environments. The balanced and unbalanced serial connectivity options enable conformity to a customer's specific application.
Customers can choose among a number of network module options to precisely fit their requirements:
• NM-1CT1-One-port Channelized T1/ISDN PRI
• NM-1CT1-CSU-One-port Channelized T1/ISDN PRI with Channel Service Unit (CSU)
• NM-2CT1-Two-port Channelized T1/ISDN PRI
• NM-2CT1-CSU-Two-port Channelized T1/ISDN PRI with CSU
Note: The 2600 and 3700 Series only supports PRI network modules without a LAN connection.
Note: The 3631 Series is not supported.
For midrange, high-density ISDN PRI applications, the Cisco 2600/3600/3700 provides superior performance and port densities. For example, a fully configured Cisco 3640 can support 8 ISDN PRI ports in one chassis, which can be multiplexed to provide up to 192 T1 channels at 56/64 kbps T1, or 240 E1 channels at 56-64 kbps.
These PRI and FE/PRI network modules support the 3600 and 3700 internal digital modems in the 3600 and 3700 for PRI, CT1, and R2 connections. This allows up to 30 V.90 modems in a 3620 or 60 V.90 modems in a 3640.
Figure 1. High Density ISDN Applications
Table 1. Physical Limitations of ISDN PRI Modules per Chassis
Number of Modules per Chassis
Type of Module
Cisco 3745
Cisco 3725
Cisco 3660
Cisco 3640
Cisco 3631
Cisco 3620
Cisco 2600
NM-1CT1, 2CT1
4
2
6
3
N/A
1
1
NM-1CT1-CSU, 2CT1-CSU
4
2
6
3
N/A
1
1
NM-1CE1B, 2CE1-B
4
2
6
3
N/A
1
1
NM-1CE1U, 2CE1-U
4
2
6
3
N/A
1
1
NM-1FE1CT1, NM1FE2CT1
N/A
N/A
N/A
4
N/A
2
N/A
NM-1FE1CT1-CSU, NM-1FE2CT1-CSU
N/A
N/A
N/A
4
N/A
2
N/A
NM-1FE1CE1B, NM-1FE2CE1B
N/A
N/A
N/A
4
N/A
2
N/A
NM-1FE1CE1U, NM-1FE2CE1U
N/A
N/A
N/A
4
N/A
2
N/A
Table 2. Cisco IOS® release requirements for ISDN PRI modules
LEDs-Network module status indicator, status LEDs, including carrier detect, local/remote alarm, and loopback. Network interfaces-All supported by Cisco 3700/3600/2600 LAN Routers.
