ombouw cisco console kabel voor GPS kit

Rebuilding a Cisco console cable for serial + power cable for the GPS kit.

A cisco cable is meant to connect a pc or laptop to the console port of a Cisco device. The cable is a set containing these parts:

Two adapters: one from female DB-9 to female RJ45, and one from female DB-25 to female RJ45. We only use the first one.
A piece of flat 8-wire cable with a RJ45 plug on both ends (cross-over wired).

The original wiring of this Cisco cable with its DB9-RJ45 adapter is according to this table:

signal (PC)	DB-9 adapter	color	RJ45 adapter	flat RJ45 cable	flat RJ45 cable
(out) RTS	7	blue	1	1	8
(out) DTR	4	orange	2	2	7
(out) TXD	3	black	3	3	6
ground	5	red	4	4	5
ground	5	green	5	5	4
(in) RXD	2	yellow	6	6	3
(in) DSR	6	brown	7	7	2
(in) CTS	8	white	8	8	1

Notice that the flat RJ45 cable is a so-called "roll-over" cable, where 1 to 8 is connected with 8 to 1 respectively on the other end.

The RJ45 connector of the GPS kit is described here (only relevant signals shown):

contact	direction (GPS)	level	description
8	input	supply	supply. +5V stab. or +10 tot +25V unstab. (SW5)
7	both	ground	ground
6
5
4
3	input	RS232	NMEA data port input.
2	output	RS232	NMEA data port output.
1

To create a cable with which the serial information can be transported to the pc's serail port and the power supply is inserted on the RJ45 cable the wiring inside the DB9-RJ45 adapter needs te be changed.

Prepare the USB or PS/2 cable by cutting it at the correct length (the distance between the USB or PS/2 port and the serial port of the laptop) and strip the cable in such a way that the 2 wires that contain the power supply are left over. (look here)

Push the 4 plastic hooks aside and retract the DB-9 connector
Drill a hole of the correct size in the plastic cover and insert the supply cable.
Cut the red, green and black wire but keep the length from the DB-9 as long as possible.
Cut the orange, white, blue and brown wire, directly on the DB-9 connector.
Cut the yellow wire so there is a piece of wire available on both sides.
Strip the wires over a few millimeters. Keep the wires tightly with a tool - if you stress the wires in the connector too much you will destroy the adapter.

Make the following connections:

the black wire from DB0 pin 3 to the yellow wire of the RJ45 (data from laptop to GPS)
the yellow wire from DB9 pin 2 to the brown wire of the RJ45 (data from GPS to laptop)
the red wire from DB9 pin 5 to the orange wire of the RJ45 (ground between GPS and laptop)
the ground or 0V wire from the USB of PS/2 cable to the green wire of DB9 pin 5 (ground between supply and GPS)
the 5V from the USB of PS/2 cable to the blue wire of the RJ45 (+5V from laptop to GPS)

Use short pieces of thermal schrinking tube to isolate the joints, and use a tie-wrap over the supply cable to secure it in the adapter. Make sure the power supply jumper on the PCB is in the 5V position.

Double-check the wiring, and connect the cable to the laptop or PC and the GPS receiver. Check the supply voltage on the GPS module - it should be between 4,75 and 5,25V.