REQUIREMENTS/SPECIFICATIONS
2-2
•
The TRMIM-42A and TRMIM-44A support IBM shielded
twisted pair (STP) cable Types 1, 2, 6, and 9 at their trunk
coupling unit (TCU) ports.
UTP CABLE TYPES
Both UTP concentrator modules (TRMIM-22A & 24A) support
D-inside wiring (DIW) voice grade Unshielded Twisted Pair (UTP)
cable as described in
EIA SP-1907B
. Voice grade UTP cabling (e.g.
IBM Type 3 UTP) must conform to the limits shown in Table 2-1.
The increased popularity and cost advantages of UTP cable have
driven refinements to UTP cable design. As a result, better grades
of UTP cable, known as supergrade or level 4, are becoming
available that exhibit improved transmission characteristics. These
improved grades of UTP can often be used to permit operation at
16 Mbit/s on longer lobe cables.
Attenuation and Impedance
The maximum attenuation for UTP cabling is shown in Table 2-1.
The values listed include the attenuation of the cables, connectors,
patch panels, and reflection losses due to impedance mismatches in
the segment.
NOTE:
IBM Type 3 - Consists of four Unshielded Twisted Pairs of 24
AWG solid wire for data or voice communication and is typically used to
wire cable runs within the walls of buildings.
Table 2-1 UTP Voice Grade (IBM Type 3) Specifications
Frequency
Impedance
Attenuation
1 Mhz
100
Ω
±
15%
<26 dB/km (8 dB/1000 ft)
4 Mhz
100
Ω
±
15%
<56 dB/km (16 dB/1000 ft)
10 Mhz
100
Ω
±
15%
<98 dB/km (30 dB/1000 ft)
16 Mhz
100
Ω
±
15%
<131 dB/km (40 dB/1000 ft)
