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Icom IC-229H Hand Mic Alternatives....

Discussion in 'Microphones, Speakers & Audio Processing' started by KC9VRY, Apr 7, 2012.

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  1. KC9VRY

    KC9VRY Ham Member QRZ Page

    Hey Guys,
    I recently acquired a really nice Icom IC-229H but without a hand mic. The radio originally came with the HM-56A hand mic which has a DTMF keypad and up/down buttons. However these microphones are hard to find on the used market and usually expensive. Now, I can get the HM-36 for around $25 on ebay which is great but it's a bare bones hand mic, No DTMF, just a mic and PTT.

    Now, what I would preferably like to do is get an HM-133 which can be had on ebay for $16. It is newer than the HM-56, has DTMF, up / down, ect... It has an RJ-45 jack connection for its cord in which I could easily switch out for an 8-pin DIN to interface to my IC-229H transceiver....

    However,,, I have no clue how the internal circuitry of the HM-133 compares to the HM-56 as I cannot find the schematics for either mic. I have an 8-pin circular connector ready to accept whatever mic, I just need to find one that is now compatible with the IC-229H

    Any suggestions?
  2. W9GB

    W9GB Ham Member QRZ Page

    Last edited: Apr 8, 2012
  3. KC9VRY

    KC9VRY Ham Member QRZ Page

    Hey Buddy!
    Thanks for the GREAT info. I went ahead and bit the bullet and bought a 3 month subscription on I have downloaded many manuals from them in the past months and can't stand waiting 4 days for the next one. Good marketing ploy! Well worth the $7 though. Now I have both the HM-56A and 133 manuals and I'll have to take a close look and see if their different chipsets will function identically on the output.

    I especially like your "internals" link but I'm a little confused as to why you say "steer clear" of the 133's.... I didn't see anything specific as to why they would be a bad mic for a retrofit to my IC-229H. Please let me know if I'm missing something.

    Anyone have suggestions on other mics that may work well with my 229H but also have DTMF???
    Thanks Again!
  4. KC9VRY

    KC9VRY Ham Member QRZ Page

    Anyone? Please?
  5. W9GB

    W9GB Ham Member QRZ Page

    If you read all of the Internet sources provided, it should be fairly obvious that these Icom Hand Mike (HM) models are really remote control devices (keyboards) with a microphone.

    As the schematics show, there is no DTMF audio encoder IC in that microphone.
    As such, they have their own uProcessor and now talk in digital code (not published - reverse engineered) to their specific radios. The DTMF audio is created in radio or via an option board.

    1. Never make the assumption that a 4x3 keypad on a modern microphone can perform DTMF.
    This was true in for 1970s and 1980s microphones and radios .... Not recent production models.

    2. Heathkit, Drake and other mfg. offered DTMF microphones -- repeater auto-patch was common (1970 - 1995), before widespread mobile phone (cellular) usage. Break-up of AT&T in 1984 changed everything -- again.

    DTMF pads were taken from Western Electric telephones and interfaced to 2-meter radios
    (DIY was very common, 1 in 4 Americans had mfg. knowledge and skills in 1970s
    In 2012 that ratio is 1 out of 12 !!)

    CES Wireless still makes a DTMF microphone for Land Mobile Radio (LMR) Service.

    Last edited: Apr 10, 2012
  6. KC9VRY

    KC9VRY Ham Member QRZ Page

    Hey Greg,
    Thanks again for the information. I was assuming that the chip in either handset was what produced the modulation for the DTMF independently to the radio.

    Anyway, as of yesterday, problem solved!!!

    After reading your last reply, I went on ebay looking for deals on Icom handsets then looking up the schematics on After a little research I surmised that the HM-118 did in fact have a chip solely for DTMF modulation as it had no "data out" leads. I ended up buying this sucker from china for only $20.00 shipped.

    After receiving the mic, I immediately noticed it was a "knock off", Not a REAL Icom mic but the build quality wasn't terrible. Now, I had the problem that the connection for this mic is RJ-45 and not the circular 8-pin connector I needed. So, I ripped the mic apart and traced all the wires to their individual functions. The chip on this mic is an ATMEL MC programmed to inject a DTMF signal into the mic lead. After finishing my tracing, I installed a cicular 8-pin connector and hooked it up to the Icom.

    IT works!! All functions, the backlight, up/down buttons, mic, PTT, DTMF,,,,, Everything!

    Anyway, I'm happy to have solved my missing mic problem for $25 and a little research.

    Thanks Again!
  7. W9GB

    W9GB Ham Member QRZ Page

    GREAT. They never said some challenges would be easy to solve :)
    A write-up on adapting this HM-118 microphone for your Icom IC-229H radio
    or addition to the existing Wiki documents, will be helpful for other amateurs.
  8. KC9VRY

    KC9VRY Ham Member QRZ Page

    Well, I don't really think it was a challenge. I re-wire stuff every day. I'm just glad I could do it for cheap and that I didn't just buy and try the HM-133 without getting second opinions. Good call on that my friend. :D

    I don't think it's really worth a writeup or wiki but definitely worth pictures and a description of pinout. Basically, you could use this cheap, knock-off handset on any radio you care to add a DTMF keypad. So, that's pretty cool.
  9. sw33tp34

    sw33tp34 QRZ Member

    Did you ever take those pictures or make that write up? Suffering from the same problem. Even tried the work around where you remove the capacitors. (After having ICOM send me new ones. No dice.) I'm ordering an HM-118 as we speak and would love to see what your pinouts were.
  10. WB0LQC

    WB0LQC Ham Member QRZ Page

    I too would like the data. I'd like to get the exact same mic Adam did from Ebay and get it re-wired. My hands are just too trembly to do any of that close in solder work, but that mic he found on Ebay sure looks nice and new and Adam figured out how to make it work. I've sent him a PM as I don't find an email address to contact him by....
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