Eight Position (RJ-45) Modular Cable - Ethernet


T568B (with clip down)	T568A (with clip down)

UTP consists of 4 twisted pairs. The standard colors are:

white/blue - blue
white/orange - orange
white/green - green
white/brown - brown

Hub to Hub or
Computer to Computer connection: one end T568A, other end T568B (Crossover Cable).

Hub to Computer connection: T568B on each end.

T1 Back to Back Cabling

Constructing a Cross-Over Cable

The T1 CSU/DSU has a different pinout than the four-wire 56k CSU/DSU. The connector for the T1 CSU/DSU is an RJ-48C. The connector for the four-wire 56k CSU/DSU is an RJ-48S. Both connectors are compatible with RJ-45 plugs.

T1 CSU/DSU Cross-Over Pinout

From RJ 48C Pin	To RJ-48C Pin
1	4
2	5
4	1
5	2

Make the first end a T568B:

Pin            Wire color

1                Orange/White

2                Orange

3                Green/White

4                Blue

5                Blue/White

6                Green

7                Brown/White

8                Brown

Make the other end:

Pin            Wire color

1                Blue

2                Blue/White

3                Green/White

4                Orange/White

5                Orange

6                Green

7                Brown/White

8                Brown

56k CSU/DSU Cross-Over Pinout

From RJ 48S Pin	To RJ-48S Pin
1	7
2	8
7	1
8	2

Tip: You can actually use a Cisco rolled RJ-45 cable (CAB-500RJ=) as a four-wire 56k cross-over cable. Even though the polarity is wrong, the bi-polar signal will be interpreted correctly by the CSU/DSU.

T1 CSU/DSU Configuration

Set one CSU/DSU to clock source internal, and the other CSU/DSU to clock source line. The linecode, framing, data-coding, and timeslots must be set the same on both CSU/DSUs.

Four-Wire 56k CSU/DSU Configuration

Set one CSU/DSU to clock source internal, and the other CSU/DSU to clock source line. On the CSU/DSU with internal clock, the clock rate must not be auto. Both CSU/DSUs must be set for service-module 56k network-type dds.