Up one level (MTR2000 Index)
Up two levels (Main Moto Index)
Back to Home
  MTR2000 External Repeater
Interfacing Signals Summary

By Robert W. Meister WA1MIK
  Print this Page


This is a collection of interface connection points for the MTR2000 stations. It's been compiled from other articles and web posts that I've run across. I've checked each of them for reasonableness and made corrections where appropriate. The suggestions in each category are presented in no special order.

For simple repeater controller interfacing, the following signals are usually required:

Important Notes:

Some signals are marked "not recommended" and you should avoid these unless there are no other options available.

All audio signals should utilize a 10uF 16V electrolytic capacitor in series with any external equipment as the station's audio circuitry is biased at +4.8VDC. Point the positive end towards the MTR2000. Some controllers may already have capacitors in series but always check first.

Logic signals are measured relative to ground.

Most connections are made to the System Connector J5) located on the rear of the station. Others will be on any exposed connector such as the MRTI (J7), Wire Line (J6), and front panel service microphone (P5602, not recommended). That's about all you can readily access.

The male mate for the system connector can be obtained from Motorola as part # TKN9205A or 3083908X02, which includes about 30 pre-crimped pins and wires for at least $50US. You can buy just the connector from Mouser, part # 571-5650889-5 for about $5US. Digikey has them as well; search for DIN 41612, 96-pin male. You just solder wires to the pins where you need them.

The MRTI connector is a DB25F, so you will need a DB25M connector to plug into it.

Other Resources:

The following articles provide useful interfacing information for the MTR2000:

Programming Hints:

You'll need a Wire Line board installed to use the wire line for audio and you will need to set it for Full Duplex (4-wire).

If you'll be using the MRTI interface, it has to be enabled in the RSS. In the Station Configuration screen, make sure the "MRTI Enable" box is checked. In the same screen, you want to set the station up as a base station, NOT a repeater. The external controller will want to see the station as a separate receiver and transmitter.

In the Personality, Channel Information, Audio screen, set the Analog RX Activation to Carrier & PL/DPL. Make sure you check the Pre-Emphasis, De-Emphasis, and MRTI boxes (as required) for the active channel. Do NOT put a call sign into the station ID field.

In the Personality, Channel Information, PTT screen, make sure the Timeout boxes are unchecked. The external controller will handle all timeouts.

PTT Input:

TX Audio Input:

There are several ways to get audio into the station, all through its standard connectors. These are:

Carrier Detect (COR) Output:

Some repeater controllers have one input for COR and a separate input for PL/DPL Detect. The station's microprocessor decodes the PL/DPL. There's both a COR output that only depends on carrier, as well as a COR output that requires a proper PL/DPL tone to be present along with that carrier. This one responds to any RF signal on the receive frequency. If you'll be using PL/DPL on your repeater, don't use this as the only COR signal.

RX Audio Output:

Receive audio comes in two flavors: raw or flat (discriminator or detected) audio, and de-emphasized audio. Neither is squelched or muted.

Carrier with Coded Squelch Output:

Some repeater controllers have one input for COR and a separate input for PL/DPL Detect. The station's microprocessor decodes the PL/DPL. There's both a COR output that only depends on carrier, as well as a COR output that requires a proper PL/DPL tone to be present along with that carrier. This one requires a carrier and PL/DPL. If you'll be using PL/DPL on your repeater, this is the COR signal you want to use.

Power Signals:

+14V is available at limited current (under 1A) to power your controller.

Ground:

Don't rely on the chassis mounting screws or a power supply ground. Pick up a ground on one of the connectors. Typically the analog grounds are used for TX and RX audio and the logic grounds are used for PTT and COR signals. The MTR2000 doesn't provide separate analog and logic grounds.

Acknowledgements and Credits:

MTR2000, PL, DPL, and a bunch of other terms are trademarks of Motorola, Inc.

Contact Information:

The author can be contacted at: his-callsign [ at ] comcast [ dot ] net.

Back to the top of the page
Up one level (MTR2000 Index)
Up two levels (Main Moto Index)
Back to Home


This page conceived 09-Oct-2014


Article text and hand-coded HTML © Copyright 2014 by Robert W. Meister WA1MIK.

This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.