Cisco ONS 15300 Series

Field Notice: ONS 15327 Some DS1 Cables May Not Have Repeated Tx and Rx Twisted Pairs Identified

October 25, 2004

Products Affected


Top Assembly

Part #

Hardware REV













Problem Description

Some ONS 15327 DS1 cables shipped from Cisco's worldwide shipment centers may not have a binder to identify repeated colors for transmit (Tx) and receive (Rx) tip/ring twisted pairs. This does not inhibit the cable's performance. The cables may be utilized, but may create some confusion as to which twisted pairs colors are repeated.


As a part of the multi-service capabilities of the Cisco ONS 15327, up to 28 DS1's are available per ONS 15327 chassis. Each of the two ONS 15327's Mechanical Interface Cards (MICs) have front access to 14 DS1 Tx and Rx connections via female AMP CHAMP type connector. Cisco offers DS1 cables that are specially connector-ized and offered for use with the ONS 15327. These DS1 cables provide a male AMP CHAMP type connector and twisted pairs matched to the 15327's DS1 connector on the MIC card, the other end with an un-terminated or whip/bare-end.

Each cable has 64 wires, and 56 wires/28 pairs are used for the Tx-Rx/Tip-Ring connections, 8 remaining wires are unused. The connector termination of the DS1 Tx and Rx is as follows:


As shown in the above table, the identified spare twisted pairs are not utilized and should remain un-terminated.

Additionally some of colors are repeated, so to assist in identifation of which of the DS1 twisted pairs that are repeated, some DS1 cable assemblies will have a binder to identify the repeated twisted pairs colors. Cisco has discovered that some suppliers of this cable do not have the identifier/binder included which makes identification of the repeated colors difficult.

The repeated colors which should be in the binder group correspond to the following pins and colors. These are also shaded in the above table.

  • Pin 26 - blue/white

  • Pin 27 - white/orange

  • Pin 28 - white/green

  • Pin 29 - white/brown

  • Pin 30 - white/slate

  • Pin 31 - red/blue (spare)

  • Pin 32 - red/orange (spare)

  • Pin 58 - blue/white

  • Pin 59 - orange/white

  • Pin 60 - green/white

  • Pin 61 - brown/white

  • Pin 62 - slate/white

  • Pin 63 - blue/red (spare)

  • Pin 64 - orange/red (spare)

Repeated color wires correspond to the indicated connector pin. For some cables these are specifically identified in a binder group.

Problem Symptoms

Some DS1 cables may not have the binder to identify repeated colors. This may cause confusion for installation technicians as to which twisted pairs are repeated, making termination of specific DS1's difficult.


An Ohmmeter or other continuity testing device may be utilized to check the continuity of the repeated color twisted pairs to identify which are terminated on the connector end of the cable. Once the repeated twisted pairs are identified, the installation technician may then complete the cable installation and terminate all the required twisted pairs on the bare/whip-end of the DS1 cable.

How To Identify Hardware Levels

Cables that do not have a binder may be identified by referencing the Top Assembly Number (TAN) and Revision, which is physically indicated on each cable assembly. Cables with a TAN number/revision indicated above do not have a binder to identify repeated twisted pairs colors.

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:

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