Serial to USB cable - varying results

[Mike, K8LH]

I do it a bit differently and so I am able to connect even the lowliest 8-pin 12F683 project to USB for a modest $2.68 investment (plus the cost of connectors).

I use a 'clone' Nokia CA-42 cell phone cable (USB to TTL level serial) available from one of several different Chinese vendors on eBay which uses the Prolific PL-2303 IC instead of an FTDI IC. Here's one of the vendors I use; Nokia CA-42 + CD, $2.68



I cut off the connector on the cell phone end of the cable and replace it with a 3.5mm "stereo" plug. I wire up the WHT (phone Tx), GRN (phone Rx), and BLK (ground) wires. I put a matching 3.5mm "stereo" jack on my PIC project boards and I'm in business (no MAX232 or equivalent level shifter IC required). Please note that there is no 5v wire in the cable (bummer!).

I've been using a 3.5mm "serial port" jack on my project boards for years (to save space) along with a simple two transistor RS232-to-serial adapter cable. Now I have the luxury of using those project boards with the RS232-to-serial adapter cable or the new USB-to-serial adapter cable.



The image above is of a successful serial bootloader download using my CA-42 USB-to-Serial cable.

Regards, Mike, K8LH

[keithdoxey]

Great tip Mike.

Looked a bargain at $2-68 then I discovered it INCLUDED shipping !!!!

Got 2 on the way to me now

[rmteo]

I cut off the connector on the cell phone end of the cable and replace it with a 3.5mm "stereo" plug. I wire up the WHT (phone Tx), GRN (phone Rx), and BLK (ground) wires. I put a matching 3.5mm "stereo" jack on my PIC project boards and I'm in business (no MAX232 or equivalent level shifter IC required). Please note that there is no 5v wire in the cable (bummer!).

Regards, Mike, K8LH

Do you know if perhaps other signals are available on this cable - in particular RTS and CTS? Thanks.

[Mike, K8LH]

Well, it's kind of a "good news" and "bad news" situation, I'm afraid...

The PL-2303 circuit board on the "business end" of the cable includes pads for 3.3v (<50ma), 5v (<100ma), RTS, CTS, etc. but since the cable is molded you have to cut away the blue plastic molding and the black rubber potting underneath to access to the circuit board. Here's what you end up with;



It seems that each new generation of clone cables are cheaper then the last. If you check out the original Jonathan Thomson article that caught my attention you'll find that earlier versions of the cable had a removable shell at the USB end and had more wires to work with and so that's kind of a bummer(!).

Regards, Mike

[rmteo]

Thanks for the info and the link.