IEEE 1284 Cables Assemblies

In order to guarantee high performance operation, 10M cable lengths, and interoperability among various platforms and peripherals, the 1284 standard defines the characteristics for the cable assemblies.

Contrary to popular belief, there is no such thing as a "standard" parallel printer cable. This typically refers to a cable assembly with a DB25 male on one end and a 36 pin Champ plug connector on the other end. Internally, the cables may have from 18 to 25 conductors, with 1 to 8 ground wires, they may have foil shielding and/or braid, and possibly a drain wire. With this type of assembly there is no way to control the cable impedance, crosstalk, capacitance and performance. This type of assembly is fine for operation at 10K bytes per second at 6 ft., but will not work reliably at 2M byte per second at 30 ft. cable lengths.

Some of the parameters for a compliant 1284 cable assembly include:

1. All signals are twisted pair with a signal and ground return
2. Each signal and ground return has a characteristic unbalanced impedance of 62 +/- 6 ohms over the frequency band of 4 to 16 MHz
3. The wire-to-wire crosstalk is to be no greater than 10%
4. The cable will have a minimum of 85% optical braid coverage over foil.
5. The cable shield shall be connected to the connector backshell using a 360 degree concentric method. A pigtail connection is not acceptable.
6. Compliant cable assemblies shall be marked with: "IEEE Std 1284-1994 Compliant"

Please refer to the 1284 standard for the complete list of requirements for a compliant

cable assembly. The standard defines a number of different cable assembly configurations. For information on the various connector types, click here. The following is a list of the available assembly types:

AMAM

Type A Male to Type A Male

AMAF

Type A Male to Type A Female

AB

Type A Male to Type B Plug

AC

Type A Male to Type C Plug

BC

Type B Plug to Type C Plug

CC

Type C Plug to Type C Plug

Standard cable lengths are available in 10 ft., 20 ft. and 30 ft. from some manufacturers. Since this cable has such good performance there is no need to be limited to a 6 ft. cable assembly.

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