Cisco 4000 Series Integrated Services Routers

Cisco Packet-over-T3/E3 Service Module Data Sheet

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The new Cisco® Packet-over-T3/E3 Service Module (SM-X-1T3/E3) provides high-speed WAN access for Cisco Integrated Services Routers (ISRs). The T3/E3 service module provides this connectivity on Cisco 2900 Series, 3900 Series, and 4451-X (ISR4451-X) Integrated Services Routers. The T3/E3 module offer both service providers and enterprise customers unprecedented flexibility in provisioning clear-channel T3 or E3 connections (Figure 1).

Figure 1. Cisco T3/E3 Module

The Cisco Packet-over-T3/E3 Service Module for the Cisco Integrated Services Routers offers the first software-configurable T3/E3 product from Cisco. This flexible T3/E3 module allows you to switch between T3 and E3 applications with a single Cisco IOS® Software command. This feature offers you increased flexibility and investment protection by allowing a Cisco partner, service provider, or enterprise customer to stock only a single product that can be deployed internationally.

The increased demand for bandwidth over the WAN and more attractive pricing of T3/E3 links by service providers has led to steady growth in T3/E3 deployments around the world. The T3/E3 module eliminates the need for an external data service unit (DSU), reduces provisioning costs, and 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, simplifying the T3/E3 line management, reducing provisioning cost, and freeing valuable rack space.

The T3/E3 module supports the proprietary subrate and scrambling features of T3 DSU vendors such as Digital Link, Larscom, and ADC Kentrox. Subrate support in the module maximizes the utility of these products in service provider environments. By simultaneously supporting interoperability with a wide range of third-party DSU vendors, this module offers the flexibility to support installed equipment without locking customers into a proprietary solution.

The Cisco T3/E3 Service Module provides direct connectivity to a T3 line for full-duplex communications at the T3 rate of 44.736 MHz and 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 and one for receive data, along with six LED indicators for line status. The T3/E3 module is supported in all Cisco IOS Software feature sets, and there are no additional memory requirements.

Key Benefits

The combination of T3 and E3 options in a single module provides the following important customer benefits:

Physical space savings: Eliminates the need for external DSU device, saving valuable rack space

Simplified management: Eliminates the need for two separate monitoring tools

Software-configurable T3/E3: Provides the flexibility to deploy a single module worldwide

Key Features

One-port T3 with DSU or E3 with DSU module

T3/E3-specific features for monitoring, bit error rate tester (BERT), MIBs, alarms, and more

Ability to independently or simultaneously enable scrambling and subrate in each DSU mode; support for the following DSU vendors' algorithms: Digital Link, Kentrox, Larscom, Verilink, and Adtran

Support for the serial encapsulation protocols: Frame Relay, Point-to-Point Protocol (PPP), and High-Level Data Link Control (HDLC)

16-bit cyclic redundancy check (CRC)

Key Management Features

Line and payload loopback capabilities

DS-3 remote-line loopback (through Far-End Alarm and Control [FEAC] codes per American National Standards Institute [ANSI] T1.107a)

Response to embedded loopback commands

Insertion of loopback commands into transmitted signal

Programmable pseudorandom pattern up to 32 bits long, including 223, 220, 215, 1s, 0s, and alt-0-1

32-bit error count and bit-count registers

Alarm detection-Alarm indication signal (AIS), remote alarm, far-end block error (FEBE), and out of frame (OOF)

Onboard processor for Maintenance Data Link (MDL)

T3/E3 Applications and Positioning

The Cisco T3/E3 Service Module provides the performance requirements to deploy advanced voice, video, and data applications over the WAN and supports key Cisco IOS Software features and services such as quality of service (QoS), Network-Based Application Recognition (NBAR), IP Security (IPsec), Firewall, intrusion detection system (IDS), Network Address Translation (NAT), and NetFlow. Table 1 gives performance recommendations for positioning of the module in the branch office (Figure 2).

Table 1. Cisco T3/E3 Service Module Branch-Office Positioning and Platform Support Matrix

Supported Platform

Recommended Type of Service

Maximum Number of T3/E3 Modules Supported

Minimum Cisco IOS Software Version (IP Base Feature Set or Later)

Cisco 2911, 2921, and 2951

Full-rate T3/E3 with concurrent services


15.2(4)M4, 15.3(1)T2, 15.3(2)T1

Cisco 3925 and 3925E

Full-rate T3/E3 with concurrent services


15.2(4)M4, 15.3(1)T2, 15.3(2)T1

Cisco 3945 and 3945E

Full-rate T3/E3 with concurrent services


15.2(4)M4, 15.3(1)T2, 15.3(2)T1

Cisco 4451-X

Full-rate T3/E3 with concurrent services



Figure 2. Typical Cisco T3/E3 Service Module Deployments


Table 2 lists the product number and description, and Table 3 lists the LED port indicators and status for the Cisco T3/E3 Service Module.

Table 2. Product Name and Description

Product Number



One-port clear-channel T3/E3 Service Module

Hardware Specifications

DS-3/E3 Specifications

DSX-3 level interface with dual female 75-ohm BNC coaxial connectors per port (separate RX and TX)

Full-duplex connectivity at DS-3 rate (44.736 MHz)

Full-duplex connectivity at E3 rate (34.368 MHz)

Scrambling and subrate support of major DSU vendors

Line build-out programmable for up to 450 feet of 734A or equivalent coaxial cable or up to 225 feet for 728A or equivalent coaxial cable

C-bit or M23 framing for T3; bypass and G.751 framing for E3 (software selectable)

Binary three-zero substitution (B3ZS) (T3) or high-density bipolar with three zeros (HDB3) (E3) line coding

Support for 16- and 32-bit CRC (16-bit default)

DS-3 FEAC channel support

Twenty-four-hour history maintained for error statistics and failure counts

DS-3 alarm and event detection (once-per-second polling)



Line code violation (LCV)

Excessive zeros (EXZ)

Far-end receive failure (FERF)

Table 3. LED Port Indicators and Status

LED Indicator


Active State Description



Loopback mode is on.



Port is receiving AIS.



Port is receiving FERF signal.



Service module is enabled.



Port is receiving OOF errors.



Loopback mode is on.

Serial Encapsulations



Frame Relay

Physical Specifications

Single-wide service module, no slot restrictions

Dimensions (H x W x D) 1.55 x 7.10 x 7.2 in. (3.9 x 18.0 x 18.3 cm)

Environmental Specifications

Operating temperature: 32 to 104°F (0 to 40°C)

Storage temperature: -4 to 149°F (-20 to 65°C)

Relative humidity: 10 to 90%, noncondensing

Certification Compliance

DS-3 Physical Layer

ANSI T1.102 and T1.107

E3 Physical Layer


ITU-T G.703 andG.823



United States (UL1950 3rd Edition/CSA C22.2, No.950)

Canada (C1950)

UK (BS6301, EN60950, EN41003)

Germany (TUV GS)

France (EN60950, EN41003, NFC98020)

AS/NZS 3260 (Australia/New Zealand)

EN60950/EN41003 (Europe)

IEC 950 (national deviations)


47 CFR 15: 2001 Class A (FCC)

ICES003 Class A

EN55022 Class A: 1998

EN300386: 2001

EN55024:1998, EN50082-1:1997 and EN61000-6-2: 1999 including:

- ESD: EN61000-4-2

- Radiated Immunity: EN61000-4-3

- Burst Transients: EN61000-4-4

- Surges: EN61000-4-5

- Injected RF: EN61000-4-6

- Dips + Sags: EN61000-4-11

EN61000-3-2: 1995

EN61000-3-3: 1995

AS/NZS 3548 Class A

VCCI V-3/2000.04 Class A


T3/E3 MIB (RFC 1407)

Cisco and Partner Services for the Branch Office

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