DIY Pro-95 Interface Cable from Cheap USB to TTL Module?

[LetterX]

I have a Pro-95 that I need an interface cable for, but I'm not keen on spending $30 from GRE or $35 from Radio Shack. From what I've read, these cables are USB to Serial to TTL adapters. Can I use a cheap $5 USB to TTL adapter off eBay, and just wire it up to a 1/8" plug? If so, should I set the TTL adapter to 3.3V or 5V (apparently there's a jumper). I'm talking about a TTL adapter like this one on eBay, and hook it up like this:

Will that work?

 

[jamesa53]

Not to discourage your efforts, but the 20-047 cable may be in stock at a local radio shack, its discontinued and sells for about 19 dollars.......this cable will work just fine with your 95. By the time you buy the phone plug end of it and the wire Ill bet you will have close to $10 in it....

 

[LetterX]

Not to discourage your efforts, but the 20-047 cable may be in stock at a local radio shack, its discontinued and sells for about 19 dollars.......this cable will work just fine with your 95. By the time you buy the phone plug end of it and the wire Ill bet you will have close to $10 in it....

I've got plenty of 1/8" jacks and wire in my "junk bins," so my only expense would be the $4.88 TTL module (free shipping). The two closest Radio Shacks to me don't have the 20-047 cable, only the 20-546 cable ($35). Besides, even if they had it, soldering on three wires is easier than getting in the car and driving to Radio Shack, and it will save me > $15. I'm even thinking about taking the scanner apart and trying to fit the TTL board inside of it, then replace the 1/8" jack with a mini-USB jack from an old broken MP3 player. That way a standard USB cable will plug right into the scanner.

Just need to know if the TTL module will work.

Of course, if someone has a spare interface cable they want to send me for the cost of shipping...

 

[W6KRU]

The driver for the computer might be a problem but that would be dependent on the software you use.

 

[LetterX]

The driver for the computer might be a problem but that would be dependent on the software you use.

Thanks, but what exactly does the software need be able to do in order for it to work? I assume the TTL module will be accessible on a COM port after the driver is installed. I was going to use the freeware program called "win95" from Starrsoft (PRO-95 Software - Win95 - Data Management for the RadioShack PRO-95 Trunking Scanner). In the configuration, you manually set the COM Port (from 1 to 256), and there are check boxes for the following options:

Extra Write Time
This may be necessary for some USB -> Serial converters (e.g. the iogear GUC232A)

Set RTA Line HIGH
This may be necessary for some home-built cables

Enable "Readback" Tests
This is to verify that all written data is correct. It must be UNCHECKED when using a one-way cable, and perhaps other "unsupported" cables.

 

[W6KRU]

It sounds like you should be in good shape if the module shows up as a com port.

 

[jamesa53]

You are going to need a driver for it, you won't be able to plug it in and it works automatically. The RS 20-047 cable uses an FTDI driver. What kind of driver this would need I do not know. Maybe one of our experts like DonS can give some advice on this.

 

[LetterX]

You are going to need a driver for it, you won't be able to plug it in and it works automatically. The RS 20-047 cable uses an FTDI driver. What kind of driver this would need I do not know. Maybe one of our experts like DonS can give some advice on this.

There's a link to download the driver from the auction for the cheap USB-to-TTL module ($4.88 shipped). I asked the seller, and he confirmed that once the driver is installed and the module is inserted into the USB port, then a standard COM port will be assigned to it. Looks like all I have to do is configure the scanner software to that COM port, and I should be good to go. Unless someone else here thinks otherwise, in which case I would really appreciate hearing why.

 

[Temelin1]

Hey LetterX: Did your DIY cable end up working?