Low Cost Icom CI-V interface

[W4JLE]

Radio shack has a cable 020-289 used to program the Pro-95 scanner. It replaces the Icom CI-V interface. The cost $24.99. I am using one with Ham Radio Deluxe and it works perfectly!

73 Fred W4JLE / NNN0AAG

[KB7DTI]

I am using one but I'm having trouble. When the program opens, it says it is having a error in hamradiodeluve.exe. I'm not very computer savvy, could you help? Tnx KB7DTI Jim:(

[NC7U]

http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif

[KB0HNN]

Anyone else tried this cable yet? I bought one, and it sends freq/mode to my icom just fine, but doesn't poll the data from the rig to automatically fill in my log.

[KE5FRF]

Funny that this topic came up. I just received my free sample Max-232 chips from Maxim integrated products in the mail Saturday and am working on homebrewing a CI-V interface cable from internet plans. The product of these #plans is **supposed** to perform to the same standard as the Icom OPC-478 cable, which is a logic level converter (RS-232 standard to TTL/CMOS)

Here is a schematic available on the internet drawn by VK2ZPT for an OPC-478 compatable cable. This is the one I am going to build.
http://www.geocities.com/heathtech123/OPC-478_Schematic.jpg
Thanks to VK2ZPT, the artist, and I asume designer of this circuit, for making it available on the internet for amateur use.

A few months back, I built another cable based on a two transistor design, but it did not work properly. I can't remember the URL or I would post it, but I have since heard criticism about the design being incompatable with some radios and/or serial ports. I think the key to why the MAX-232 design will work is the ability to draw power from the DTR and RTS pins of the serial port.

I am no RS-232 standard expert, but I have been doing some research to learn more. It is not enough for me to simply build the project, but I want to learn something from it too.


If anyone is interested, here is how I have surmised the cable works (PLEASE, if anything I comment on is incorrect, PLEASE correct my mistakes!!:

RS-232 serial ports work on a negative logic principle. The threshold voltage for any logic state is +or- 3 volts. Anything inbetween is considered the threshhold region. A voltage of -3 volts or more is considered a logic 1, and a voltage of +3volts or more is considered a logic 0. The operating voltage of a DB-9 serial port is around 24 volts give or take, but I think the measureable voltages of any RS-232 pin will actually be less than 14 volts, perhaps due to built in loading resistors.

According to this schematic, I surmise that at any given time pins 4,7 (DTR and RTS) will be in a logic 0 state
(remember, logic is reversed or negative)....meaning that one pin or the other will be supplying positive operating level voltage (which is more than 5 volts). The forward biased diodes D1 and D2 insure that given at least one pin is at a positive voltage level, the other pin, while potentially below ground level, will not short the other pin out. Thus, these diodes protect both pins when the other is in the opposite state, and also maintain a positive biased voltage on the cathode side of both diodes. Thus, after being regulated by 78L05, a five volt regulator, and noise filtered by the 33uF and 1uF caps, a stable 5 volt supply voltage is created for IC1 (max-232)

And the rest is fairly simple to understand too. Since we have established that a serial RS-232 standard port works on a negative or reversed logic principle, it is easy to comprehend why the MAX-232 IC is needed to convert that signal to TTL or CMOS level data for our radio. Pins 2 and 3 of the DB-9 (dataRX and dataTX respectively) are designed to understand this "funky" logic. The center pin of our radio is designed to recieve and transmit normal ones and zeros. So here is how data is sent and recieved from the RS-232 to the radio and back to the RS-232 through IC1......

Pin3 of RS-232 goes to pin 13 of IC1 in RS-232 proticol. An amplifier inside the IC converts the signal to the "usual" 5 volt logic signal in which 5 volts represents a logic 1 and 0 volts represents a logic zero. #This data stream is sent to the center pin of the 3.5mm stereo plug (NOT THE TIP!!) and deciphered by the radio uProcessor, and stored in the radios memory. When the computer requests information from the radio, the process is reversed, and TTL level information is sent from the radio to IC1, which goes through a different amplifier to change the logic back to the RS-232 standard, and thus the computer is able to process information from the radio. I surmise that the diode D3 is in place to keep this data stream sorted out on the radio side, since the data is being multiplexed onto a single conductor. It keeps TX data seperate from RX data, and vice versa, acting as a "block valve" for data bits.

Anyway, this is my interpretation of how this interface works, but I'm no expert, and would really like to have some experts critique my interpretation.

BTW, I wonder if this cable will work for Yaesu radios as well. I assume so as long as the center conductor on the stereo plug is used for sending and recieving data.

[KB0HNN]

Well just one comment, in the schem, there is a switch to flip the data line between the tip and ring. According to the schematic of my icom 726, only the tip and sleve are used. Maybe the newer CIV are different and require a 'stereo' plug.

I also breadboarded the 4 transistor interface as shown on the CIV website, with the same results of one way data. And yes I have poped the cover on my rig to check that the transceive option is selected with the diode.

[KE5FRF]

Ok, I see that..I didn't really pay close attention that part of the schematic, taking for granted that the OPC-478, which is my cable of interest, needs the center conductor wired. I see now that the switch permits the cable to be used to replace more than one style.

So, do you agree that this cable, if built correctly, should work as stated? In my application, I am going to use it to program my V8000.

Also, if I understood your comment, you built the 4 transistor model, and it didn't work correctly, only allowing one way data transfer?

As I said, I'm not an RS-232 guru, but I've been reading up to learn more.

[KB0HNN]

If you do a quick google search for CI-V, the first hit is CI-V &#39;bible&#39;, in there is a few different versions of the RS232<>CI-V interface. One is shown with a max232, but different values of caps no diode. I&#39;ve actually seen a few versions with the max232, but don&#39;t know enough about them to say if yours would work or not. Compared with the others, they all look about the same.

Yes I built one with 4 transistors, as shown in QST 7/92 by KG7SG. Schematic is also shown at the plicht.de site. I can send data to the radio with it, but can&#39;t receive data from the radio. I&#39;ll have to dig in a little deaper tonight with the o-scope and try to figure it out. The interface cable I bought from radio shack as listed at the top of this thread does the same thing, send data to the radio just fine, but no rcv data from radio. I&#39;m starting to think I have a software problem instead.

[N3ATS]

Buy one, it&#39;s all you need.

I&#39;ve used the OPC-478 to program three different radios. All you need to do is change the connector that connects to the radio.

OPC-478 (3.5mm stereo plug) to program and control the IC706MKIIG use a stereo to mono adapter. To program the Yaesu FT8800 I homebrewed a box to plug he 478 into using a female stereo jack. The other side is a section of keyboard cable with a DIN plug.

[KB0HNN]

Well I solved my problem, after tearing into my homemade interface and cables. I found one of the lines wrong on my 232 cable. Man it&#39;s easy to over look some of the dumb mistakes even when you look at it half dozen times.

RS cable still doesn&#39;t work. I tore it apart to find a small circuit board with a 8 pin IC and a couple SM components. A search for the IC number brought back nothing. Maybe some type of PLC?

[KE5FRF]

Quote[/b] (KB0HNN @ Jan. 24 2006,14:36)]Well I solved my problem, after tearing into my homemade interface and cables. I found one of the lines wrong on my 232 cable. Man it&#39;s easy to over look some of the dumb mistakes even when you look at it half dozen times.

RS cable still doesn&#39;t work. I tore it apart to find a small circuit board with a 8 pin IC and a couple SM components. A search for the IC number brought back nothing. Maybe some type of PLC?
Well, I don&#39;t know, but a lot of times those numbers are proprietary and they don&#39;t publish the datasheets.

Is there a symbol on the IC that might indicate the semiconductor producer?

A lot of times a quick call will at least let you know if the IC is generic or proprietary.

[KB0HNN]

no symbols, but here is the numbers/letters

062
F003B
JRC

[KE5FRF]

Quote[/b] (KB0HNN @ Jan. 24 2006,21:03)]no symbols, but here is the numbers/letters

062
F003B
JRC
Well, my first google search for JRC led me to conclude the IC is made by Japanese Radio Company (http://www.jrc.co.jp/eng/index.html). Since they manufacture amateur radio products, I think it is a safe bet that they are the company who made that IC.

I didn&#39;t see an American Ph# on the website, but it is a lead, anyway.

[KE5FRF]

Here (http://www.profusionplc.com/jrc.htm) is another URL, for Japan Radio Company component lookup. Maybe we can find your IC here.

I didn&#39;t have any luck, but my guess is either the component is obsolete, or proprietary.


On edit...may be getting somewhere...

Another company makes a low power transmitter IC with the part number MICRF003BM.( From what I gather, getting this description on Google: "MICRF003BM SOIC-16L OOK 900MHz Lw Pwr RF Micrel Transmitters".)

The datasheet for this IC can be obtained at this url (http://www.partminer.com/pagedetail/5411/33), but you have to subscribe to their website.

I didn&#39;t quite catch the application in which this IC was involved with the CI-V discussion, but I hope this helps.

After going back in the thread, you say the IC came out of the RadioShack CI-V cable. Hmmm. It is certainly plausible if not likely that RS contracts out such cables to Japanese Mfrs. So, the JRC company, I think, is a good bet.

Now, the low power transmitter IC, though the part number is similar, I can&#39;t picture how a 900MHz RF transmitter would be integrated in a logic level converter cable, unless it was wireless http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif , so maybe I went off on a tangent with that one.