The ID-O-Matic IV is an improved version of the ID-O-Matic III. I added an audio amplifier with moderate gain to reduce the number of users having trouble getting enough audio to their transmitter. There is also now a separate volume control for the voice ID board. All other functions are the same as the ID-O-Matic III, and it runs the same firmware.
The big question is: "How does the ID-O-Matic IV compare to the ID-O-Matic II and III?"
The ID-O-Matic IV is a multipurpose, microcontroller based device intended primarily for repeaters, but with other uses as well. With a heritage dating back to the original ID-O-Matic featured in the 2008-2012 ARRL Handbook, its primary application is that of a simple but feature-laden repeater controller with automatic Morse code station ID. It can also be used for beacons, fox hunt transmitters, automatic station ID and many other uses. Thousands of ID-O-Matics have been sold to hams around the world and are in use in beacons, repeaters, link transmitters, Echolink & IRLP stations, and even providing automatic CW ID for HF, VHF and UHF stations.
So what are the more interesting features? There's a programmable delay timer that announces your call sign or any other message, in Morse code at a speed and audio tone you choose. Then there are the CW keying and PTT outputs so you can attach it to a transmitter, transceiver or repeater. The COR/squelch input can be used to make a repeater controller/IDer that works the way you want it. And how about a new USB interface to connect to your shack computer, laptop or terminal for quick and easy configuration? It's all there.
Using the built-in USB interface, connect the ID-O-Matic IV to a PC (Windows, Mac, or Linux) with a free terminal emulation program such as PuTTY or Minicom and you can use the simple menu to configure the ID-O-Matic IV the way you want it. Just type in your ID message. When the COR input is activated the ID-O-Matic IV will send the message at regular intervals. And now, with the optional add-on voice ID board -- record your own voice ID and use that instead of (or in addition to) Morse code!
The COR input is used to control when the ID-O-Matic IV sends your programmed Morse code ID. You can use a squelch, COR, PTT or other signals from your equipment according to your needs. The built-in interface circuit and programmable signal polarity let you use either active-high or active-low input signals. You can optionally have the ID-O-Matic send a courtesy beep (or up to three Morse code characters) at the end of each transmission, and you can specify a "hang time" to keep PTT active for a brief period after the input stops. If you want the repeater to ID every so often when it's idle, there is a beacon timer and a separate message for that too. You can, for example, have the repeater ID with its call sign while being used, and a longer message every hour or two when it's idle. Or use Morse for the regular ID, and a voice announcement for the beacon. The ID-O-Matic IV has a real-time clock, so you can synchronize the beacon ID to the wall clock if you want.
There's a PTT watchdog timer to keep your repeater from being "hung" by stuck mic buttons or long-winded users. And, you can use the ALT MSG input to send a different ID message (and even change the courtesy beep) based on the state of an input signal - useful if, for example, your site switches to backup power, or if a link is active. For an example of how you could use the ID-O-Matic IV in a repeater setup, there is a nice write-up here: http://www.repeater-builder.com/kenwood/pdfs/tkr-n20-idomatic.pdf
Regardless of the mode used, the PTT output is active during the CW ID, with a programmable pre- and post-ID delay. Speed is variable from 5 to 40 words per minute, and the audio pitch for the CW ID and the courtesy beep is also programmable via the setup menu. All outputs are equipped with robust 2N7000 MOSFETs that can handle up to 60V at up to 200 mA to key transmitters or other loads.
Improvements have been made to the original ID-O-Matic's Morse audio output. The -IV boasts a smooth, nearly pure sine wave audio signal rather than the raspy square wave found in some ID circuits.
The on-board Morse ID is filtered and fed to a passive audio mixer with volume control. An input is provided for external audio from your receiver or other source; this input also has a volume control and is mixed with the Morse audio. There is a de-emphasis filter on the external audio input that can be included or left off at build time, depending on your needs.
"Future-Proof": The heart of the ID-O-Matic IV's functionality is the firmware program that controls the processor. The controller can be upgraded with new firmware in minutes, without the need to return it for programming, swap chips or even remove it from the repeater (although a few minutes of down time is required). New features are planned for future release, giving you added capabilities at no added cost.
The ID-O-Matic IV kit includes the new ID-O-Matic IV chip along with a high quality, double-sided PCB with silkscreen and solder mask. All parts needed to build the board are included. All you need to supply is an enclosure and a source of power. If you want to see the instructions before ordering, please see the Downloads tab on tihs page for a PDF copy.