T1 T-Extender and Amplifier

T-1 Repeater and Amplifier for customer owned cable

  • T-1 4-wire repeater
  • T1 demark extension - extends in-house T-1 lines
  • Up to 5000 feet between units (depending upon cable)
  • RJ-45 or screw down connectors
  • Simple connection to a 4-wire T1 line
  • Inexpensive solution to long T-1 runs
  • 120/240 VAC, 12, 24, -48, or 125 VDC power options
  • 1-U rack mount bezel or 20 slot chasis
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RJ-45 adapter or screw terminals may be used in either or both ports.

Unit supplied with two screw terminal and two RJ-45 adapters.



Download the Manual (PDF version)

Application Notes


Installation Accessory Kit

How to order


The DCB T-Extender is a 4-wire T-1 repeater for use on customer owned t1 lines. The T-Extender is a t1 repeater used to extend in-house T-1 lines in campus and high-rise environments.

Note: This product is NOT intended for 10BaseT or Ethernet. T1 modulation is designed for use with twisted pair solid wire phone cables. The T-extender does NOT extend ethernet connections... only T1 connections. To extend ethernet 10/100/100BaseT cables, see our Ethernet-Extender here.

Each pair of T-Extenders may be located up to 5000 feet apart. Solid copper 22 AWG two twisted pair is the preferred cable for connection between T-Extenders. Smaller wire sizes will reduce the functional distance between T-Extenders. Connection to the T-Extender is made through RJ-45 modular connectors or 4-wire screw down barrier strips. Both types of connectors are standard on the T-Extender.

The DCB T-Extender is often powered by a small wall-mount transformer. 12, 24, -48, and 125 VDC versions are available. It is used to extend connections between T-1 equipment such as PBXs, T-1 multiplexers, T-1 line drivers, T-1 local multiplexers or any other T-1 equipment requiring long customer owned cable runs. T-Extenders may be used to connect this equipment across a campus, between floors of a high-rise office building or between office buildings with underground cable connections.

While stand-alone units are most commonly used, a 1U rack mount is available that mounts three T-Extenders in a 19" rack. A 20 slot chasis is also available which contains up to 20 board-level T-Extenders and common power supplies.

T-Extenders can also be used to extend the distance between any T-1 equipment (DSU, channel bank, router, etc.).

The T-Extenders are best used in pairs. If you have a T1 CSU that is limited to 655 feet, connected to a device limited to 655 feet, and you put the T-Extender at one end, the T-Extender will drive the extra distance. However, the far end device will still be limited to 655 feet and will not likely have sufficient "drive" to reach the far end. The T1 transmitted signal is the issue addressed by the T-Extender, so in this case, the line would be error-prone or possibly only work in one direction. For cable runs greater than about 5,000 feet, additional T-Extenders may be cascaded

T-1 repeater
Extends T-1 bi-polar signal
Up to 5000 feet between T-Extenders
Up to 5000 feet to equipment with ALBO (Automatic Line Buildout)
Up to 655 feet from ABAM signalling equipment with 4-wire cross connect cabling
Two twisted pair solid copper 22 or 24 AWG; standard telco T1 cable if UTP category rated cable is used, CAT 3 is recommended.

We do NOT recommend CAT 5 cable. Although it often works well, CAT 5 cable has been shown to cause problems with many T1 installations.

Other cable types will affect operational distance.

Front panel power LED
Two connectors on the rear panel (A & B). These connectors are interchangable and each uses one of the following.
RJ-45 modular 8-conductor connectors (A & B)
With "To Telco" Connector # 9502122
Pin 1 = Receive +
Pin 2 = Receive -
Pin 4 = Transmit -
Pin 5 = Transmit +
With "To Customer" Connector # 9502172
Pin 1 = Transmit +
Pin 2 = Transmit -
Pin 4 = Receivet -
Pin 5 = Receive +
4-wire screw down barrier strips # 5003011 1 = Receive +
2 = Receive -
3 = Transmit -
4 = Transmit +
Connect T-Extender transmit pair to the receive pair of the next T-Extender or T-1 equipment. T-Extender is not polarity sensitive.

A cable cross-over is required between two Extenders if using straight RJ-45 cables. This cable connects the receive pair of one Extender to the transmit pair of the other Extender.

Connectors A and B are electrically identical. Either one may be used as the "demarc" side or the "CPE" side of the Extender.

Power requirements: 120 VAC, 3 watts wall mount transformer or
12, 24, -48, 125 VDC, or 240 VAC optional
Temperature: -40C to +70C Humidity: less than 95% non-condensing 7" x 5 1/4" x 1 1/2"
Rear view of DCB T-Extender with one of each connector
(shown without anodized panel to emphasize the connectors)
9902095 Rack with three T-Extenders

Installation Accessory Kit

Many technicians installing T-Extenders for the first time don't have all the cables required to set up a pair of T-extenders and demonstrate that the T-1 line and other equipment operates properly on a work bench, or in the telephone closet. This kit includes all the parts needed to install two T-Extenders and the CPE within reach of the telephone company demarc, as well as a physical loopback RJ-45 plug to use diagnosing any problems that occur. Parts included are one T-1 straight-through cable, two T-1 crossover cables, two RJ adapter boards, and one T-1 RJ loopback plug.

Application Note

Solving T-1 Problems with the T-Extender This application note illustrates how to solve common T-1 demarc problems by using the T-Extender. The T-Extender is a no-configuration T-1 repeater/extender that allows a T-1 line to stretch 5,000 feet or longer. Read the application note here.

T-1 T-Extender, Tips, Tricks, and Diagnosis An in-depth discussion on the quickest way to install, test, and diagnose problems with T-1 extender or repeater problems. This is the documentation provided in our recommended T-1 installation accessory kit. Written specificially for our T-Extenders, but it applies to any T-1 repeater. T-Extender, Tips, Tricks, and Diagnosis

T-1 Cables and Cross-Talk We receive many questions about what kind of cable works best for T-1 extensions. Many people mistakenly believe Cat-5 or Cat-6 LAN cable works well. Here's the scoop... a technical discussion about why you should use real T-1 cable for every T-1 installation, and some manufacturer's part numbers. T-1 Cables and Cross Talk



One "To Telco" RJ-45 connector, One "To Customer" RJ-45 connector, and two screw terminal connectors are included with each T-Extender.
Item Number Description Price Buy Now!
T-Extender T-1 Line repeater for up to 5000 feet w/ 120VAC power input $ 550 Qty:
T-Extender/12VDC T-1 Line repeater for up to 5000 feet w/ 9-18 VDC power input $ 625 Qty:
T-Extender/24VDC T-1 Line repeater for up to 5000 feet w/ 19-36 VDC power input $ 625 Qty:
T-Extender/48VDC T-1 Line repeater for up to 5000 feet w/ 36-72 VDC power input $ 625 Qty:
9501030 External 125 VDC power supply for standard T-Extender $ 125 Qty:
9500095 Customer's T-Extender to telephone company demarc straight-through RJ45 cable $ 12 Qty:
9500099 Customer equipment to customer equipment T1 RJ45 crossover cable $ 12 Qty:
9502122 Additional -To Telco- RJ adapter $ 12 Qty:
9502172 Additional -To Customer- RJ adapter $ 12 Qty:
5003011 Additional screw terminal adapter $ 12 Qty:
T1-KIT T-1 installation accessory kit $ 49 Qty:
9500106 T-1 loopback plug, RJ-45/48C $ 5 Qty:
9902096 19" rack bezel for a single T-extender $ 30 Qty:
9902095 19" rack shelf for 1 to 3 T-extenders $ 75 Qty:
L-1 20 slot 19" rack chasis $ 1,680 Qty:
9902090 Optional DIN rail mounting clips $ 5 Qty:

Data Comm for Business Inc.
2949 County Road 1000 E
Dewey, Il 61840
Voice: 217-897-6600
Toll Free: 800-4-DCB-NET
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Web: www.dcbnet.com
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