2. CI-V level converter
To connect the CI-V bus line to a computer you need a converter, which converts the +/-12V of the RS-232 interface to 0V/+5V of the open collector bus line. ICOM offers such a device, called the CT-17. But there are several designs to build your own converter, the schematics are all fairly simple (and cheaper).
Here are some proposals for a converter:
- Yet another... although with a special benefit. This design by Greg, W8WWV uses the well known MAX232 chip, but has an extra transistor for driving the PTT. A much needed function for many programs using the soundcard.
- A very nice commercial product by Heinz, HB9KOF which does opto isolated CI-V conversion among other things. ARDI-1001 interface by HB9KOF
- Yet another example for a simple transistor interface by Bill, G3MCS
- Gary sent me a design for an opto isolated IF with very low power needs.
- Interface using transistors only (from KG7SG, QST 7/92)
The original, (probably where i copied this schematic from :-) can be found here: AA6YQ website.
- Interface using MAX232 IC (from the ICOM CI-V spec. 1986)
- Small Interface using transistors
- CI-V interface and band switching unit from Bob, K6XX
- Optoelectronics, Inc. supports the CI-V interface in many of their products. They provide in their "Technical Documents" file area yet another schematic for an RS232 to CI-V interface.
- The site of K4PWO (ex AF4XQ), with another design using the MAX233 chip. With a board layout.
- Yet another design with the LTC1383 by Howard, KD6UU listed on eham.net or on Howards homepage at qsl.net . Uses power from the serial interface, very small.
- Another design with two transistors by Dave, G3VGR G3VGR converter Uses power from the serial interface, very small.
- A note from mdf at angoss.com:
I've found that one can use a Yaesu ADMS programming cable as a CIV level converter -- just stick a 3.5mm stereo -> 2.5mm mono adaptor on the end of it. Simple, cheap, effective. [The ADMS cable is about 1/4 the price of the CT-17, and probably worth buying instead of building your own converter.]
- The most expensive CI-V level converter? An IC-R8500 IC-7800! This rig offer both, a CI-V jack and a normal RS-232 serial interface. But it also acts as a converter between both interfaces. Same applies for the IC-R75 and IC-R8500. So if you own an IC-7800, IC-R8500 or IC-R75 and more Icom rigs, you don't need a converter at all, just use the rig.