3com S27x User Manual

A-6 

Cables

This cable may have a maximum length of up to 100m and must conform to the 
802.3 10BaseT specification, with a nominal impedance of 100 ohms. Category 3, 4, 
or 5 cable may be used. Category 4 or 5 is preferred.

Refer to ANSI/TIA/EIA 568A and the following references:

• CSMA/CD Access Method and Physical Layer Specifications, IEEE standard 

802.3-1992.

• Draft supplement to IEEE standard 802.3, System Considerations for Multi 

Segment 10B/S Baseband Networks (Chapter 13) and Medium Attachment 
Unit and Baseband Medium Specification, Type 10BaseT (Chapter 14), 
p802.3i-1990.

The following table shows the Ethernet RJ-45S connector signals.

The AIU cable uses male DB-15 to female DB-15 connectors with slide latches in a 
straight-through connection.

The twisted pair combinations are 1/2, 3/6, and 4/5, and may be used for Ethernet.

This cable may have a maximum length of up to 50m and must conform to the 802.3 
10BASE5 specification.

The following table shows the Ethernet DB-15 connector signals.

1

Transmit  +

2

Transmit  -

3

Receive +

6

Receive -

1

Shield

2

Collision+

3

Transmit+

4

Shield

5

Receive+

6

Ground

8

Shield

9

Collision-

10

Transmit-

11

Shield