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Page 2-6

The supported STP cable types meet the following specifications:

consists of two shielded twisted pairs (STP) of 22 AWG solid 

wire for data. Used for the longest cable runs within the walls of 
buildings.

 consists of six pairs of unshielded twisted pairs of 24 AWG 

solid wire and a shield casing. The two pairs carried within the shield 
casing are used to carry Token Ring data. The four pairs carried outside of 
the shield casing are typically used for voice communication. Type 2 is 
frequently used to wire cable runs within the walls of buildings.

 consists of two STP of 26 AWG stranded wire for data. 

Because of its high attenuation, Type 6 is used only in patch panels or to 
connect devices to/from wall jacks

. Attenuation for Type 6 cable is 3/2 x 

Type 1 cable (attenuation for 66 m of Type 6 = attenuation for 100 m of 
Type 1).

 is similar to Type 1, but uses 26 AWG solid wire. Like Type 6, 

because of its high attenuation, Type 9 is used only in patch panels or to 
connect devices to/from wall jacks

. Attenuation for Type 9 cable is 3/2 x 

Type 1 cable (66 m of Type 9 = 100 m of Type 1).

The physical length of the cable connecting a station to a TCU port on the 
concentrator is referred to as the lobe length. The maximum lobe length 
attainable with the concentrator, under ideal conditions, is shown in Table 

Table 2-3. STP Cable Type Specifications.

IBM

Type

Operational

Frequency

Impedance

Attenuation per...

1000 m 

(1000 ft)

1 & 2

 4 MHz

≤

 150

Ω

  

±

15%

≤

 22 dB

(

≤

   6.7 dB)

16 MHz

≤

 150

Ω

  

±

15%

≤

 45 dB

(

≤

 13.7 dB)

6 & 9

 4 MHz

≤

 150

Ω

  

±

15%

≤

 33 dB

(

≤

 10.0 dB)

16 MHz

≤

 150

Ω

  

±

15%

≤

 66 dB

(

≤

 20.0 dB)