Comtrol PCI User Manual

RocketPort® ISA and PCI Series

Building Loopback Plugs

Hardware Tech Tip

Introduction

Loopback plugs are used with the diagnostic software to
test serial ports. This Hardware Tech Tip discusses
building loopback plugs for use with the following
RocketPort cards:

• RocketPort ISA- and PCI-bus boards that use an
external RS-232 or RS-232/422 interface box

• RocketPort ISA- and PCI-bus boards that use the
Quadcable or Octacable interfaces

• RocketPort 4J or 8J boards

Note: The Hardware Installation Cards contain

information about how to build loopback plugs for
the RocketPort 485 and RocketPort PCI 422 cards .

Building DB25 Male Loopback Plugs

Wire the following pins
together for an RS-232 plug.

• Pins 2 to 3

• Pins 4 to 5 to 22

• Pins 6 to 8 to 20

Wire the following pins
together for an RS-422 plug.

• Pins 15 to 19

• Pins 17 to 25

Pin 13 Pin 1

Pin 25

RS-232 Only (Back View)

Pin 13

Pin 25 Pin 14

RS-422 Only (Back View)

Pin 14

Pin 1

Building DB9 Female Loopback Plugs

Wire the following pins together for
an RS-232 plug:

• Pins 1 to 4 to 6

• Pins 2 to 3

• Pins 7 to 8 to 9

Pin 1

Pin 6

RS-232 Only
(Back View)

Building RJ45 Loopback Plugs

Wire the following pins together for an
RJ45 plug:

• Pins 4 to 5

• Pins 1 to 8

• Pins 2 to 6 to 7

18

Plug

Top View

Cable

Building RJ11 Loopback Plugs

Wire the following pins together for an
RJ11 plug:

• Pins 1 to 5 to 6

• Pins 3 to 4

16

Plug

Top View

Cable

Pin 5

Pin 9

Building DB25 Female Loopback Plugs

Wire the following pins
together for an RS-232 plug.

• Pins 2 to 3

• Pins 4 to 5 to 22

• Pins 6 to 8 to 20

Wire the following pins
together for an RS-422 plug.

• Pins 15 to 19

• Pins 17 to 25

RocketPort® ISA and PCI Series Building Loopback Plugs Hardware Tech Tip 1 of 2

Pin 14

RS-232 Only (Back View)

Pin 1

RS-422 Only (Back View)

Pin 13Pin 1

Pin 25

Pin 13

Pin 25Pin 14

Technical Support

Comtrol has a staff of support technicians available to help
you. Before you call, please have the following information
available:

• Model number

• Serial number

• Interface type

• I/O address and IRQ

• Operating system type and release

• Device driver version

• PC make, model, and speed

• List other devices in the PC and their addresses

Comtrol Headquarters Europe

Phone [phone] [phone]
FAX [phone] [phone]
Email [e-mail] [e-mail]
web site www.comtrol.com www.comtrol.co.uk
ftp site ftp.comtrol.com

First Edition, August 10, 1999
Copyright © 1999 Comtrol Corporation
All Rights Reserved.

RocketPort is a registered trademark of the Comtrol
Corporation.

Other product and company names mentioned herein may
be the trademarks of their respective owners.

Comtrol Corporation makes no representations or
warranties with regard to the contents of this reference
card or to the suitability of any Comtrol product for any
particular purpose. Specifications subject to change
without notice. Some software or features may not be
available at the time of publication. Contact your reseller
for current product information.

2000042 Rev A

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