How to Terminate a 250 Pair Telecommunications Cable

The telecommunications cabling industry uses multi twisted pair copper cable and multi-fiber optical cable to link telecommunications equipment. The BIX cross-connect system is a set of hardware and components that connect various copper cabling mechanisms together to create a structured cabling system.

These instructions explain how to terminate a 250-pair unshielded twisted pair cable onto the BIX cross-connect system so that the cable can be cross-connected to other horizontal (workstation) distribution cables.

Figure 1 is an example of a small cross-connect system where the single mount on the left is the 250-pair backbone field and the two mounts on the right are a horizontal (workstation) distribution field. Cross-connects will be made between the two fields to create a connection path. These instructions explain how to terminate onto the backbone field.

Caution: •Follow telecommunications cabling standards that are established by ANSI TIA-EIA 568B •Follow Ontario Building Codes and Standards


  1. 1
    Install the BIX Mount - Note: The BIX Mount must be installed on a 34 inch (1.9 cm) plywood backboard that has been treated with a fire retardant product or that has been covered with a fire retardant paint. This is a practice that is mandated by Ontario Building Code. - Fasten the mount to the plywood backboard with two (2) 34 inch (1.9 cm) no.8 wood screws. Screw holes are provided on the mount. Use a level to ensure that the mount is squarely installed.
  2. 2
    Image titled Figure 3 1
    Install the BIX Distribution Rings - Fasten one ring to the top right corner and one ring to the bottom right corner of the mount.
    The rings will snap into place. Next fasten each ring to the backboard with two (2) 34 inch (1.9 cm) no.8 wood screws.
  3. 3
    Image titled Figure 4 1
    Mount the 250-pair Cable - Fasten the cable to the BIX mount with nylon tie wraps.
    There are four knock outs on the mount that tie wraps can slide into. Use the right bottom knock out and secure the cable. Leave 1 meter (3.3 ft) of slack on the cable.
  4. 4
    Strip the cable - The 250-pair cable will have ten (10) Secondary bundles of 25-pairs (50-conductors). Each 25-pair bundle will be wrapped in a color coded yarn. Two (2) Primary bundles of five (5) 25-pair bundles will also be wrapped in a color coded yarn. It is important to maintain the bundles so that the conductors can be terminated in the correct sequence. - With a utility knife, score the outside sheath of the cable but make sure not to pierce the sheath and damage the conductors. Use the ripcord to cut the sheath down to the point where the cable is mounted (tie wrapped) to the BIX mount. Carefully remove the sheath and cut it away while maintaining all the twisted pair bundles. Wrap electrical tape around the ends of each bundle to make sure that the color coded yarns that are wrapped around each bundle are not lost.
  5. 5
    Image titled Figure 6 1
    Fasten each 25-pair bundle - While referring to the colour codes in Figure 5, fasten each 25-pair bundle to a BIX1A connector.
    Starting with the first primary bundle (it will wrapped in white yarn), remove the yarn from the first secondary bundle, also wrapped in white yarn. Fasten the ‘white’ bundle to a BIX1A distribution connector with a small nylon tie-wrap. The connector has sleeves for accommodating the tie-wrap. Next proceed with fastening the second secondary bundle (wrapped in red yarn), followed by the third bundle (wrapped in black yarn). Once the ‘white’ primary bundles have been set, proceed with the ‘red’ primary bundle.
  6. 6
    Image titled Figure 7 1
    Seat the conductors - Each conductor will have its own painted colour code.
    Again using the colour codes chart in figure 5 slide each conductor into the appropriate slot on the BIX1A connector. The connector should be securely seated into the first slot of the BIX mount. Starting from the left end of the connector, insert the White/Blue conductor into the first slot. Then insert the Blue/White conductor into the second slot. Then insert the White/Orange conductor into the third slot. Continue with each successive conductor until all the conductors of the ‘White’ 25-pair bundle have been seated. Then proceed with ‘red’ 25-pair bundle, followed by the ‘Black’ bundle and so on… Continue until all 250-pairs of conductors have been seated. See figure 7 on how to seat conductors.
  7. 7
    Terminate the conductors - The BIX Connecting tool is a device that will cut / trim each conductor to the required length and press each conductor into the BIX1A connector. The BIX connector contains metal sleeves within its casing that make an ‘insulation displacement’ connection. When the BIX tool pushes the insulated conductor into the connector, the connector slices the insulation and makes permanent contact with the copper conductor. Insert the BIX tool into each successive slot and press firmly. The connections are made and excessive conductor lengths are removed.
  8. 8
    Image titled Figure 8
    Rotate the BIX Connectors - Each BIX1A connector must now be rotated so that the terminated 25-pair bundles are on the inside of the BIX10A mount.
    Start with the first connector at the top. Rotate each connector so that the bundles of conductors end up on the underside of the connector. Next rotate the second connector so that the bundle is on the upper side to the connector. Rotate each connector until the bundles are aligned as indicated in Figure 8.
  9. Image titled Figure 9
    Label the BIX10A mount - It is necessary in structured cabling to identify each connection and conductor. The BIX cross-connect system provides a means for identifying each connection. Use appropriate printing software to label each BIX Designation Strip as illustrated in Figure 9.
  10. 10
    Document - All telecommunications cabling should be accurately documented and referenced in a spreadsheet form. Documentation will indicate the route for the connection paths in the cabling system. This document described the process for terminating a 250-pair cable; the same process will have been performed on the opposite end of the multi-pair cable. As illustrated in figure 9 at the center of each designation label, the opposite end of this cable is “Location B”. Documentation will describe the originating end and the opposite end of each cable in the system. At “location B”, the designation labels will read “250-pair to (Location A)”. Documentation should also describe the function of each cable and the system that they serve.

Things You'll Need

  • (1) 250-pair Cat3 UTP Riser Cable
  • (1) BIX10A Mount
  • (10) BIX1A Distribution Connector
  • (2) BIX Distribution Rings
  • (1) BIX Connecting Tool
  • (1) roll of electrical tape
  • (10) nylon tie wraps
  • (10) 34 inch (1.9 cm) no.8 wood screws
  • (1) utility knife
  • (1) level
  • (1) utility knife

Article Info

Categories: Cabling and Wiring Connection