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T1 and J1 Cabling Requirements

The information in this section provides applicable specifications and recommendations for the T1/J1 cabling for the AMC348/RMC348 cards. These cable requirements are normalized to conform to the American Telephone & Telegraph (AT&T) standard which specifies Western Electric ABAM 600 (see the following table)

Note

Even though the J1 nominal requirement is 110 Ohms, typically,cablethatmeets the ABAM standards is used for J1 applications.

ABAM 600 Specifications

AttributesRequirements
Normal Impedance100 Ohms +/- 5% at 772 kHz
Insertion loss

Better than 7 dB per 308.8 m (1000 ft) at 1.544 MHz

Better than 5 dB per 308.8 m (1000 ft) at 772 MHz

Far-End Crosstalk

Better than 85 dB per 308.8 m (1000 ft) at 1.544 MHz

Better than 90 dB per 308.8 m (1000 ft) at 772 MHz

Near-End Crosstalk

Better than 80 dB per 308.8 m (1000 ft) at 1.544 MHz

Better than 85 dB per 308.8 m (1000 ft) at 772 MHz

Signal Wires22 AWG solid tinned copper
Drain Wire24 AWG solid tinned copper
Shields

Transmit and receive pairs are individually shielded.

Although the original ABAM cable is no longer available from Western Electric, nearly all cable manufacturers supply a version of the ABAM cable.

Note

Ribbon recommends that you purchase cables that meet or exceed the ABAM requirements. Consult a qualified network engineer for more information or contact  Customer Support.


Caution

The T1/J1 cabling recommendations in this document provide basic information only. Consult a qualified network engineer for specific network cabling instructions or contact  Customer Support.

The AMC348’s rear transition module RMC348 provides eight RJ48C connectors for T1/J1 cables (refer to DSC 8000 System Cards).

In general terms, the T1/J1 cable should meet with the following requirements:

  • 22 American Wire Gauge (AWG) cable that has the same characteristics as ABAM for short-haul of up to 199.64 m (655 ft.)

    Note

    24 or 26 AWG cables that have electrical characteristics similar to ABAM can also be used.

  • Two shielded twisted pair (STP)
  • Impedance rating of 100 Ohms for T1 and 110 Ohms for J1
  • Review the Installation-Specific Cabling Questions.
Note

For cable runs longer than 213.36 m (700 ft), consult with a qualified network engineer or with  Customer Support.

Example of the 22 AWG Cable with RJ48 Connectors


E1 Cabling Requirements

The E1 120 Ohms cables have the same cabling requirements as the T1 cabling (see preceding section) with the exception of the impedance rating of 120 Ohms.

E1 75 Ohm cables are not usually used for long-haul cable runs. In general terms, these E1 75 Ohm cables should meet the following requirements:

  • RJ48C connector to a Bayonet-Neill-Concelman (BNC) connector which splits the cable into two unbalanced coaxial cables (see the following figure). If both ends of the communications link have BNC terminations, two BNC to BNC cables may be used to create the link.
  • For short runs of less than 30.8 m (100 ft), RG59U based coaxial cables may be used
  • For longer runs of 30.8 to 213.36 m (100 to 700 ft), 734A based coaxial cables may be used. This coaxial cable has a better braid and shielding with less loss per foot.
  • For RJ48C E1 75 Ohm cables, verify if the outer conductor must to be grounded.
  • Review the Installation-Specific Cabling Questions.
Note

For cable run longer than 213.36 m (700 ft), consult with a qualified network engineer or with  Customer Support.

Caution

The E1 cabling recommendations in this document provide basic information only. Consult a qualified network engineer for specific network cabling instructions or contact Customer Support.

RJ48C to BNC Coaxial Connector

Installation-Specific Cabling Questions

Answer the following installation-specific cabling questions before selecting a cable:

  • Are there Restriction of Hazardous Substances (RoHS) requirements?
  • Does the cable need to be plenum rated for fire safety?
  • Are there special burn emission requirements?
  • Is the cable installation in an especially noisy environment requiring extra shielding for a cable? If yes, an extra braided overall shield, for example, can be used.
  • Are there any local installation specific requirements?


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