Ciscos Packet-over-T3/E3 network module for the Cisco 2600, 3600, & 3700 series offers the first software-configurable T3/E3 product from Cisco. This flexible network module allows the customer to switch between T3 & E3 applications with a single Cisco IOS comm&. This feature provides customers with unparalleled investment protection by allowing the service provider or enterprise customer to stock only a single product that can be deployed internationally. The demand for increased bandwidth has led to growth in clear-channel T3/E3 deployment. This new Packet-over T3/E3 network module (part number NM-1T3/E3) eliminates the need for an external data service unit (DSU), reduces provisioning costs, & provides highly manageable T3/E3 line termination. The module provides an integrated line interface unit (LIU) DSU that allows T3 or E3 lines to be directly terminated on a Cisco router, eliminating the need for external DSU equipment. This simplifies the T3/E3 line management, reduces provisioning cost, & frees valuable rack space. Offering unprecedented flexibility in provisioning clear-channel T3 or E3 connections, the Cisco T3/E3 network modules provide support for the proprietary subrate & scrambling features of T3 DSU vendors Digital Link, Larscom, & ADC Kentrox. Subrate support in the Cisco T3/E3 Network Module maximizes the utility of these products in service provider environments for tiered DS3 services. By simultaneously supporting interoperability with a wide range of third-party DSU vendors, this network module offers the flexibility to support installed equipment without locking customers into a proprietary solution. The Cisco T3/E3 Network Module provides direct connectivity to a T3 line for full-duplex communications at the T3 rate of 44.736 MHz & full-duplex E3 communications at 34.368 MHz. Each T3 or E3 port consists of a pair of 75-ohm BNC coaxial connectors (Type RG-59), one for transmit data & one for receive data, along with six LED indicators for line status. The Cisco 2650XM & 51XM, Cisco 2691, Cisco 3660, & the Cisco 3725 support a single T3/E3 network module. The Cisco 3745 supports up to two single-port Cisco T3/E3 network modules. Because the Cisco T3/E3 Network Module is supported in Cisco IOS feature sets, including IP Only, there are no additional memory requirements for any supported platforms.