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  Replace the R100 Control Board
with an ID-O-Matic Morse ID Timer

By Robert W. Meister WA1MIK
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This article was written at the request of Bob McKinlay VE3DJ with the intention of replacing the R100 repeater control board with an ID-O-Matic II Morse ID Timer. After programming and aligning the radios, the repeater control board would be completely disconnected and the ID-O-Matic II would connect directly to the repeater's receiver and transmitter radios via new two-row DA-15M connectors. You need to keep the repeater control board and all its cables present in the R100 station for programming purposes, as part of the circuitry on that board is required for interfacing to the radios. The Molex power connector is unplugged from the control board and plugged into the cable going to the radios and ID-O-Matic. JAux and its interface board, if present, are left alone.

The ID-O-Matic is a product of www.HamGadgets.com. This article was initially written for the ID-O-Matic II product and has been tested with an ID-O-Matic IV model. The commands and setup parameters are similar but as I don't have an ID-O-Matic II model, I'll have to leave the exact settings "as an exercise for the student."

Other repeater controllers may also work with the R100 radios. This was just done with the ID-O-Matic because it was inexpensive and was sitting around not being used. There are also many methods of interfacing external repeater controllers to the R100's internal controller.

Notes and Documentation:

In the rest of this article, I will use Arabic numerals (2, 3, 4) instead of Roman numerals (II, III, IV) for the ID-O-Matic models/versions. I will also abbreviate the name as "IOM".

The IOM 1 was the first version of this product in 2009 and its manual can be downloaded by clicking here. This unit was just a CW ID with timer; it did not process repeater audio and can't be used for the purposes in this article. I've included this if you're interested to see the improvements and changes made since the product was born.

The IOM 2 was the current version of this product in 2012 and its manual can be downloaded by clicking here.

The IOM 3 was the current version of this product in 2013 and its manual can be downloaded by clicking here.

The IOM 4 is the current version of this product in 2014 and its manual can be downloaded by clicking here.

The latest manual should always be downloaded from the Hamgadgets web site as the product and documentation are continuously improved.

DC voltages are measured to DC ground with the repeater disabled and no input signal. AC voltages are measured by feeding an -80dBm signal into the receiver modulated with a 400 Hz sine wave at 1 kHz deviation.

I purchased the following parts for about $0.75 each (Mouser part numbers shown):

You will also need 2 (two) 10k 1/4w resistors and 1 (one) 4.7k 1/4w resistor. If you are interfacing an IOM 2, you'll need 1 (one) more 4.7k 1/4w resistor and 1 (one) 2N2222 or equivalent small-signal NPN silicon transistor.

Here's a photo of the rear (solder side) of the DA-15M connectors showing the pin numbers. Click on the image for a larger view.

r100-iom/db15m.jpg

Radio Connector Signals:

The radio's command boards use two-row DA-15F connectors for all signals. The table below summarizes these signals and their pins. Many of the same signals are present on both radios but there may not be any supporting circuitry connected to them. The command boards are only populated with the parts needed to receive or transmit. These same radios, when used in the mobile radio environment, were fully populated to provide both receive and transmit functions.

Pin#Receive RadioTransmit Radio
1(SPARE)(SPARE)
2PTTPTT
3DETECTED AUDIO(SPARE)
4AUDIO GNDAUDIO GND
5FLAT AUDIO(SPARE)
6B+B+
7HUB/PGMHUB/PGM
8F1/F2 (DATA2)F1/F2 (DATA2)
9TX BUSY (RESET)TX BUSY (RESET)
10MIC HIGHMIC HIGH
11CARR SQUELCH DETECT(SPARE)
12(SPARE)(SPARE)
13TONE SQUELCH DETECT(SPARE)
14GROUNDGROUND
15CSQ/UNSQ (DATA1)CSQ/UNSQ (DATA1)

Controller P4 - RPTR RX Signals:

Pins 2, 4, and 7 are for programming. Pin# refers to the DA-15 connector on the receive radio.

Detected Audio is de-emphasized and has had PL/DPL filtered out of it. If you use Detected Audio for RX Audio, remove or do not install the de-emphasis capacitor in your IOM, as you don't want to de-emphasize the audio twice. Flat Audio comes directly from the receiver's detector. If you use Flat Audio for RX Audio, leave in or install the de-emphasis capacitor in your IOM, as you need de-emphasis only once. Neither source is squelched or muted; the IOM does that for you. Use a 10uF 16V DC-blocking capacitor in series with the wire going to the controller (positive end pointing towards the radio) if necessary (not needed with the IOM).

P4#VDCSignal NamePin# Notes
1- - -N/C  
24.50PTT/Data In 2 
34.92Detected Audio Out 3256 mVAC/kHz
40.01Gnd4  
54.91Rx Flat Audio 581 mVAC/kHz
613.13+13.8V6  
73.38HUB7  
86.15F1/F28 Pull up to +13.8V
9- - -N/C  
109.75Exciter Audio 10 
113.74CSQ Indicator 110.0VDC w/signal
12- - -N/C  
130.01PL Indicate 134.6VDC w/signal
14- - -N/C  
15- - -N/C  

Controller P5 - RPTR TX Signals:

Pins 1, 2, and 3 are used for programming. Pin# refers to the DA-15 connector on the transmit radio. Use a 10uF 16V DC-blocking capacitor (positive end pointing towards the radio) in series with the Exciter Audio wire going to the controller if necessary (not needed with the IOM). The audio will be pre-emphasized; this is normal for FM radios. This also means that you will need to de-emphasize the receiver audio at some point, either in the receiver (by selecting the proper audio output) or in the IOM (by installing the de-emphasis capacitor).

P5#VDCSignal NamePin# Notes
13.64HUB7  
23.56PTT/Data In 20.0VDC TX
38.71Exciter Audio/Data Out 1083 mVAC/kHz
40.01Gnd4  
56.15F1/F28 Pull up to +13.8V
613.12+13.8v6  

Controller P7 - Power Supply Signals:

This is a 7-pin Molex 0.156 inch spaced connector. The only available male ends are meant for circuit board installation, so I used one of those and insulated each terminal with heat shrink tubing. You will be unplugging this connector from the controller board and plugging it into a new wiring harness. Here's a photo of the connectors on the controller and the mating cable end.

r100-iom/pwr-conns.jpg

Here's a photo of the rear (solder end) of a new 7-pin Molex header showing the pin numbers. You'll need to heat and pull out pin 2 because a keyway plug in the mating cable end only allows the connector to be inserted one way. Click on the image for a larger view of the unmodified connector.

r100-iom/molex-conn.jpg

P7#VDCSignal NameNotes
1- - -Not Used 
2- - -Not Used Keyway; no pin inserted here
3- - -Not Used 
413.12+13.8VMain power source
56.13Low Battery Active High; needs pull-up resistor
60.00On Battery Active High; needs pull-up resistor
70.0Gnd 

Note that with no battery attached, the power supply will report "Low Battery" but since AC is present and the station is not running on the (not present) battery, "On Battery" is low. Both signals need to be high for the station's control board to emit the alarm tone. We can use the "On Battery" signal to select the alternate CW ID message.

IOM 2 Terminal Block J1 Signals:

Bob VE3DJ provided this wiring list. Remember that you're connecting to the DA-15M connectors that will plug into the transmitter and receiver radios. The TX and RX pin numbers in the "Connect To" column refer to those connectors.

Pin#FunctionConnect To Comments
1GndGnd 
2+V DC Power Input+13.8VDC 
3PTT OutputTX pin 2 
4CW Output- - - 
5Beacon Indicator- - - 
6Reset Input- - - 
7COR InputRX pin 11 or 13See Text
8RX Audio InputRX pin 3Use Capacitor
9Inhibit InputRX pin 11Active Low
10TX Audio OutputTX pin 10Use Capacitor

For the COR Input, if you want to use Carrier Squelch, connect to RX pin 11 and configure the IOM for active-low (0). If you want to use PL/DPL Detect, connect to RX pin 13 and configure the IOM for active-high (1).

You will need to wire the "On Battery" signal to the ALTMSG (labeled B0) pad on the board. This signal also needs a 4.7k pullup resistor to +13.8VDC. Read the IOM2 manual for more information. Unfortunately, this pin is always active low and is unprotected, so you'll also need an inverter transistor and another pullup resistor to utilize this input. All of this is included in the diagram below. If you don't want to go through the trouble, it's not really important and you can easily do without this feature.

An interconnection diagram can be downloaded by clicking here. Only the power and ground wires go to multiple places. The colors on the diagram just happen to match the wire colors I used.

IOM 3 and 4 Terminal Block J1 Signals:

I came up with this wiring list based on the one Bob provided for the IOM 2. Remember that you're connecting to the DA-15M connectors that will plug into the transmitter and receiver radios. The TX and RX pin numbers in the "Connect To" column refer to those connectors.

Pin#FunctionConnect To Comments
1GndGnd 
2+V DC Power Input+13.8VDC 
3PTT OutputTX pin 2 
4CW Output- - - 
5Beacon Indicator- - - 
6Reset Input- - - 
7COR InputRX pin 11 or 13See Text
8RX Audio InputRX pin 3Use Capacitor
9ID Indicator- - - 
10ALT MSG InputPS pin 6 Needs 4.7k Pullup to +13.8VDC
11TX Audio OutputTX pin 10Use Capacitor
12GndGnd 

For the COR Input, if you want to use Carrier Squelch, connect to RX pin 11 and configure the IOM for active-low (0). If you want to use PL/DPL Detect, connect to RX pin 13 and configure the IOM for active-high (1). I used PL/DPL Detect on my station.

The "On Battery" signal to the ALT MSG input needs to be pulled up to +13.8V with a 4.7k pullup resistor. The signal coming out of the power supply is an open-collector transistor that floats when the station is running on DC power.

An interconnection diagram can be downloaded by clicking here. Only the power and ground wires go to multiple places. The colors on the diagram just happen to match the wire colors I used.

Unfortunately, the IOM 3 and 4 have a slightly different pin configuration than the IOM 2. Pins 1 through 8 are identical. Pin 9 of the IOM 3/4 is an ID Indicator. There's no need to inhibit the ID on the IOM 2 when the receiver is busy; the IOM 3/4 is "polite" and handles this task for you. Pin 10 of the IOM 3/4 is an Alternate Message Selection Input that is present on a separate pad (B0) of the IOM 2. Pin 11 of the IOM 3/4 is the Transmitter Audio Output. Pin 12 of the IOM 3/4 is a second Ground. The IOM 4 is a slightly improved version of the IOM 3; both use USB and a Windows program for configuration. In most other respects the units should be fully compatible.

ID-O-Matic Configuration:

All commands are the characters you'd enter from the main menu. Commands are shown separated by semicolons but you must terminate each with the ENTER key. Read the IOM 2 manual for details on that unit. Compare the parameter values with those shown in the IOM 3/4 manuals, as the defaults may not be the same. These are the IOM 3/4 parameters that I modified from the factory default state, after a "Reset" command (C; R).

ParameterValueCommand
PTT watchdog180 secs1; 8; 180
PTT hang time5 secs1; 9; 50
CWID messageWA1MIK/R2; 1; wa1mik/r
ALT messagePF WA1MIK/R2; 1; pf wa1mik/r
COR polarityHigh or Low4; 1; 1 or 0

For the COR polarity, if you're using Carrier Squelch (RX pin 11) configure this input for active-low (0). If you're using PL/DPL Detect (RX pin 13) configure this input for active-high (1).

Remember to WRITE the changed configuration to the FLASH memory when you're done programming the IOM 3/4.

Also remember to remove the de-emphasis capacitor from the IOM if the receive audio line you utilize has already been de-emphasized.

Construction Details:

Label your new cables that go to the receiver and transmitter, as they are not interchangeable. The wiring is very straightforward; follow the wiring diagram and appropriate connection table for your IOM. I used 18 inch pieces of 8-conductor 22ga stranded cable and used the four wire colors shown in the wiring diagram. I soldered the 10k resistors directly to the DA-15M connectors; I will cover them with some electrical tape later.

I constructed the wiring harness with all the connectors first, without connecting the IOM. I could then plug the harness into the station and test the four signals going to the radios: PTT, TX Audio, COR, RX Audio. I powered the wiring harness, at this point plugged into just the two radios, from an external power supply. When idle, they drew 360mA; when transmitting, they drew 880mA. As the IOM draws less than 100mA, the total current going through the wiring harness power wires is under 1A. I grounded the PTT input on the transmitter and the station keyed up. I fed in an RF signal with PL and the PL/DPL Detect output on pin 13 of the receiver went high. Once I knew these were working properly, I wired the harness up to the IOM. I temporarily ignored the "On Battery" signal from the power supply. Here's a photo of the harness before I attached the IOM to it. Click on the image for a larger view.

r100-iom/harness.jpg

With the "On Battery" signal disconnected but pulled up to +13.8V, the IOM sent the ALT MSG ID string. I connected the "On Battery" signal and powered the station from an external DC supply; the IOM sent the ALT MSG ID string. When I plugged the AC power cord back in, the IOM sent the regular CW ID message when it was time to do so.

The F1/F2 signals on each radio are pulled up to +13.8V with a 10k 1/4w resistor at each DA-15M connector.

When you program the radios, make sure you set the Transmitter Time-Out value to 0 (zero) seconds. The IOM will control the overall timing of the repeater. Program and align the radios with the original R100 controller board attached, then disconnect that controller and install the IOM and its wiring harness. The IOM can be mounted almost anywhere, even stuck to one of the radio shields with some double-sided foam tape. There are plastic enclosures for sale on a popular online auction site. You can even add a voice ID module to the IOM 3/4 if you like chatty repeaters. Here's a photo showing the R100 control board disconnected and the IOM 4 wired up and working, sitting on top of the harness cables. Click on the photo for a larger image.

r100-iom/finished.jpg

If you're going to be interfacing anything to an R100, please don't butcher the cables by chopping the wires at the repeater controller, like the guy did to the radio in the photo below:

r100-iom/dont-do-this.jpg

Setting Levels:

The first thing to do is set the transmitter deviation. The deviation pots are on the command board, underneath the radio, so you must remove the transmitter from the station and flip it over. You may then feed audio into it. You can do this by disconnecting the TX Audio and PTT wires from the IOM and connecting your own test equipment directly to those wires. Feed a 1V 400 Hz signal into the transmitter's audio input through a 10uF capacitor and key the transmitter. Set the deviation to 5 kHz maximum with PL/DPL present. Reconnect the IOM and feed a 400 Hz modulated signal into the receiver's antenna input at 3-4 kHz and adjust the RECVR pot on the IOM for 4-5 kHz of transmitter deviation. You will get some limiting and clipping as you approach 5 kHz; don't go too high. There was plenty of receiver audio when the IOM was wired according to the article; the pot had to be turned down to about 1/4 of its full rotation. The MORSE pot can be set to whatever you think is pleasant; mine was mid-way. As I don't have a voice ID module attached, I just turned the VOICE pot fully counter-clockwise.

On my station, a 400 Hz modulated tone at 2.25 kHz deviation plus a 110.9 Hz PL tone at 0.75 kHz deviation (3.0 kHz total input deviation) resulted in about 4 kHz total output deviation. At that point, I had 526 mVAC of audio coming in from the receiver and 189 mVAC of audio feeding the transmitter. With the RECVR pot set fully clockwise I had over 1 VAC of audio available, so there's plenty of gain in the system.

I also ran a quick frequency response check on the IOM 4; it's essentially flat from 100 Hz to over 7 kHz. My test setup wasn't able to generate a large enough signal to cause the IOM to go into clipping.

Other Notes:

There are two signals that come from the power supply to indicate the station is running on battery and that the battery voltage is low. These generate an alarm tone on the R100 controller board that is heard during transmissions. I wired one of these to the IOM to select the Alternate Message instead of the normal ID.

Remember that you must completely reconnect the R100 controller board to the radios and power supply for programming and alignment purposes.

The original radio cables are easily identified. The transmitter cable only has six wires; the receiver cable has ten. The photo below shows their orientation. The receiver's connector (on the left) is down at the bottom of the cabinet and its row of 8 pins is closest to the bottom of the cabinet. The transmitter's connector (on the right) is easier to get to and its row of 8 pins is closest to the top of the cabinet.

r100-iom/db15-conns.jpg

By the way, this same cable without the IOM works great when you have to repair or align either radio on the bench. Just supply power and ground and occasionally PTT for the transmitter.

ID-O-Matic IV Audio Characteristics:

I connected the IOM 4 to some high-impedance audio test equipment and can report the following information. No audio load was attached to the IOM.

At 13.6 VDC input, the unit draws about 25 mADC. This varies +/- 5 mA depending on the LED color or if it's flashing.

The frequency response is essentially flat (+0 dB, -0.5 dB) from 50 Hz to 60 kHz. It does drop down 5 dB at 10 Hz, 2 dB at 20 Hz, and 1 dB at 30 Hz, but as that's outside the normal voice response range, it's nothing to worry about. This was with the de-emphasis capacitor removed.

The maximum output level was 1.15 VAC. Distortion was approaching 1 % at that point. This is entirely due to the audio op-amp being powered from a 3.3 V power supply, which only allows a 3.3 Vp-p output signal (this just about equals 1.15 VAC).

Distortion was below 0.2 % at 1.0 VAC output or less.

The device has a maximum audio gain of approximately 6.75; in other words, an input voltage of 0.1 VAC produces an output voltage of 0.675 VAC, with the RECVR pot fully clockwise.

Credits and Acknowledgements:

R100 information came from the R100 UHF Repeater Instruction Manual, Motorola p/n 6881078E15-O.

ID-O-Matic information came from the product's various manuals.

Big thanks go to Kevin W3KKC who loaned me an ID-O-Matic IV to build and use in two articles.

Trademarks and model names are those of their respective owners.

Contact Information:

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

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This article was created in December 2013.
This page originally posted on Thursday 21-Aug-2014.



Article text, artistic layout, and hand-coded HTML © Copyright 2013 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.