Cabletron Systems BRIM-T6 manual Shielded Twisted Pair STP, Impedance and Attentuation

MEDIA SPECIFICATIONS AND REQUIREMENTS

B.2 SHIELDED TWISTED PAIR (STP)

STP cable categories are listed as follows:

•IBM Type 1 consists of two STP lengths of 22 AWG solid wire for data. There are three versions of Type 1: Indoor, Outdoor, and Plenum. It is typically used for the longest cable runs within the walls of buildings.

•IBM Type 2 is similar to Type 1 data cable, but has four additional UTP lengths of 22 AWG solid wire carried outside of the shield casing. There are two versions of Type 2: Plenum and Outdoor. It is typically used for voice communication and often used to wire cable runs within the walls of buildings.

•IBM Type 6 consists of two STP lengths of 26 AWG stranded wire for data. Used in patch panels or to connect devices to/from wall jacks. Attenuation for Type 6 cable is 150% of Type 1 cable (e.g., 66 m of Type 6 =100 meters of Type 1).

•IBM Type 9 is similar to Type 1, but uses 26 AWG solid wire. Attenuation for Type 9 cable is 150% of Type 1 cable (e.g., 66 m of Type 9 = 100 meters of Type 1).

Impedance and Attentuation

The attenuation values shown Table B-2 include the attenuation of the cables, connectors, patch panels, and reflection losses due to impedance mismatches in the segment.

Table B-2. STP Cable Specifications

Type	Freq.	Impedance	Attenuation
1 & 2	4 MHz	150Ω + 15%	<22 dB/km (6.7 db/1000 ft.)
	16 MHz	150Ω + 15%	<45 dB/km (13.7 db/1000 ft.)
6 & 9	4 MHz	150Ω + 15%	<33 dB/km (10 db/1000 ft.)
	16 MHz	150Ω + 15%	<66 dB/km (20 db/1000 ft.)

B-2