Cisco WAN Interface Cards

Understanding the 1-Port 4-Wire 56/64 Kpbs CSU/DSU WAN Interface Card (WIC-1DSU-56K4)

Document ID: 7263

Updated: Nov 19, 2007



The 1-port 4-wire 56/64 kpbs Channel Service Unit/Data Service Unit (CSU/DSU) WAN interface card (WIC) (WIC-1DSU-56K4) is combined within a single WIC and performs the CSU/DSU functions for both DDS (dedicated) and 4-wire switched 56 kbps data networks. It also provides an all rate synchronous interface to any dedicated Digital Data Service (DDS) point-to-point or multi-point network compatible with AT&T Publication 62310. The WIC-1DSU-56K4 also supports 4-wire switched 56 data services such as AT&T's Accunet 56 or Sprint's VPN-56 plus many switched data services offered by local exchange carriers.




There are no specific requirements for this document.

Components Used

Please refer to the Platform Support section below for detailed information.

The information presented in this document was created from devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If you are working in a live network, ensure that you understand the potential impact of any command before using it.


For more information on document conventions, see the Cisco Technical Tips Conventions.

Product Number

WIC-1DSU-56K4 - One Port Four Wire 56/64 Kbps CSU/DSU WAN Interface Card


This list details the features associated with the WIC-1DSU-56K4:

  • Implements the switched 56 k and DDS (leased line) operation.

  • Identical hardware feature set to the 4-wire 56/64 k CSU/DSU for the 2524-2525.

  • Identical Cisco IOS® software configuration.

  • Supports the DDS (leased line) operation (AT&T Pub. 62310).

  • Supports DDS loop rates 2.4, 4.8, 9.6, 19.2, 38.4, 56, and 64 kbps.

  • Supports the switched 56 operation at 56 kbps (AT&T Pub. 41458, Sprint TS-0046).

  • Receiver sensitivity is -45db at all loop rates.

  • Uses the Self Test Function (at power on and user initiated) and Network line and data terminal equipment (DTE) loopbacks. User initiated DTE, line, and remote V.54 loopbacks diagnostic functions.

  • Compliant with UL 1950, UL 1459, CSA 22.2-950, CSA 22.2-255, FCC part 15J Class A, and FCC part 68.

Platform Support

Platform Cisco 1600 Cisco 1720 Cisco 2600, 2600XM Cisco 3620, 3640 Cisco 3631 Cisco 3660 Cisco 2691, 3725, 3745
Carrier Module Not Required Not Required on-board NM- 2W NM-1E2W, NM-1E1R2W, NM-2E2W NM-1FE2W, NM-1FE1R2W, NM-2FE2W, NM-2W Not Required NM-1E2W, NM-1E1R2W, NM-1FE2W, NM-1FE1R2W, NM-2FE2W, NM-2W on-board NM-1FE2W, NM-1FE1R2W, NM-2FE2W, NM-2W
Cisco IOS Software Support Cisco IOS Versions 11.2(9)P, 11.3(3)T, and all 12.x All Cisco IOS versions All Cisco IOS versions Cisco IOS Versions 11.2(4)XA, 11.2(5)P, all 11.3, 11.3T, and all 12.x All Cisco IOS versions All Cisco IOS versions All Cisco IOS versions

Note: The Cisco IOS software releases provided are typically the minimum version required to support the platform, module, or feature in question. Use the Software Advisor (registered customers only) to choose appropriate software for your network device: match software features to Cisco IOS and CatOS releases, compare IOS releases, or find out which software releases support your hardware.


The WIC-1DSU-56K4 interface card uses service-module commands. Below is a sample configuration.

Note: There are no framing or linecode commands. This is because the 56 k card is not a T1 and does not relate to timeslots. There are 24 timeslots in a T1: 24 x 64 DS0s=1.544m

This card is strictly 56 k and timeslots are not relevant.

interface serial 0/0
 service-module 56k clock rate 56
 service-module 56k clock source internal
 ip address
 encapsulation ppp
 no shut

For a list of commands available, refer to Configuring Cisco Integrated Data Service Unit/Channel Service Unit (DSU/CSU) Modules and WAN Interface Cards.

To perform a loopback test refer to Loopback Tests for T1/56 K Lines.

Connector Pinout

The WIC-1DSU-56K4 module uses a standard straight through RJ-45 cable to connect from the RJ-48S jack on the CSU/DSU to the wall jack.

RJ-48S pin Signal
1 receive ring
2 receive tip
7 ring
8 tip

LED Definitions

Label Signal Definition
DCD Data Carrier Detect Settings normal or on all the time. Normal /DDS: Illuminated when data characters are being received. Normal/SW56: Illuminated when a valid connection is established.
RD Receive Data Illuminates when receive data characters are being clocked from the DSU module into the router.
TB Transmit Data Illuminates when transmit data characters are being clocked from the router into the DSU module.
LB Loopback Solid illumination any time a loopback is active.
AL Alarm Illuminates any time an unmasked alarm condition exists:
  • OOS/OOF from network
  • no receive signal
  • no sealing current
  • no frame sync for 64 K
  • attempting to rate adapt
  • RT (DSU Loopback), LL (CSU Loopback), from Telco
  • Remote Digital Loopback (RDL) from remote DSU

Related Information

Updated: Nov 19, 2007
Document ID: 7263