IBM Cabling System Types


The IBM Cabling System consists of the following cable types


Type 1
This is a cable consisting of two pairs of 22 gauge solid wires. Each pair is individually shielded and there is an overall shield covering the entire cable. The impedance of Type 1 cable is 150 ohms. Type 1 cable is rated at speeds up to 20 Mbps.
 
Type 1A
This cable is the same as Type 1 cable but is rated at speeds up to 100 Mbps.
 
Type 2
This cable type is a hybrid. It consists of two pairs of 22 gauge solid wires which are individually and overall shieled, and have an impedance of 150 ohms. There are also four pairs of unshielded 24 gauge solid wires. This cable is basically a Type 1 cable with the addition of four unshieled pairs under the same jacket. The shielded pairs in a Type 2 cable are rated at 20 Mbps, and the unshielded pairs are rated for speeds up to 4 Mbps.
 
Type 2A
This cable is the same as Type 2 cable but the data pairs are rated at speeds up to 100 Mbps.
 
Type 3
Type 3 cable is exactly the same as Category 2 UTP. It is a four-pair 24 AWG solid wire cable rated for speeds up to 4 Mbps, and has an impedance of 100 ohms.
 
Type 5
Type 5 cable is a 100/140 micron multimode fiber optic cable. It is not currently in use for many new installations, as 62.5/125 micron size has basically replaced it for fiber optic applications.
 
Type 6
Type 6 cable can be thought of as a thinner and more flexible version of Type 1. It consists of two pairs of stranded 26 gauge wires. Each pair is individually shielded, and there is an overall shield. The impedance of the cable is 150 ohms, and it is rated for speeds up to 20 Mbps. Note that Type 6 cable has 1.33 times the loss of Type 1.
 
Type 7
Type 7 cable is a single-pair version of Type 6. It consists of a single pair of 26-gauge wires with an overall shield. The impedance of the cable is 150 ohms, and it is rated for speeds up to 20 Mbps. Type 7 cable is not often used.
 
Type 8
Type 8 cable consists of two pairs of individually sheilded 26 gauge solid wires in a heavy flat jacket. This cable type was designed exclusively for short runs under carpeting. The impedance of the cable is 150 ohms, and it is rated for speeds up to 20 Mbps. Type 8 cable has twice the loss of Type 1.
 
Type 9
Type 9 cable is a thinner version of Type 1. It consists of two individually shielded twisted pairs of 26 gauge solid wire. The impedance of the cable is 150 ohms, and it is rated for speeds up to 20 Mbps. The loss of Type 9 cable is 1.33 times greater than Type 1.

It is important to note that only Type 1, Type 2, Type 3, and Type 6 cables are commonly used in Token Ring applications. The other types were included above only for completeness. Another point which must be stressed is that the word "Type" is not to be confused with the word "Category" as it is used by the EIA/TIA to describe UTP Cables. For example, Category 5 cable is a UTP cable rated for speeds of 100 Mbps, whereas Type 5 is a fiber optic cable. Confusing the two nomenclature systems will most likely result in major difficulties.