Tech question regarding download cable

rq3

Senior Member
Is there a reason the standard USB to stereo plug download cable (AXE027?) has the sleeve of the stereo plug connected to an active signal, rather than circuit ground (as is "normal")?

Typically, that plug (sleeve, tip, ring), would be wired so that the sleeve is circuit ground, with tip and ring being active (stereo L & R, or for the Picaxe Serin and Serout).

Isolating the active sleeve from an aluminum enclosure is, frankly, a pain, and technically incorrect. If there is a plug insertion contact sequence, I cannot find it, and would welcome any thoughts on this.
 

premelec

Senior Member
There was some comment on forum... speculation that tip being hot could be shorted by fumbling newbie etc... note there is an alternative with three pins in line instead of stereo plug - I made an adaptor to convert stereo plug to 3 pin config years ago... less space on PCB... ;-0
 

inglewoodpete

Senior Member
Is there a reason the standard USB to stereo plug download cable (AXE027?) has the sleeve of the stereo plug connected to an active signal, rather than circuit ground (as is "normal")?
While I agree with you, the cable pre-dates the PICAXE. I understand that Rev-Ed were looking for a ready-made serial cable and found an economical off-the-shelf model. Once their early development boards were designed and sold and compatible with that cable, they were locked into the plug arrangement.

Posted by Technical in 2008: "Cable layout is just historical. This was the layout used with many early (serial, not USB) digital cameras, so this was the layout chosen as these camera cable were readily available at very low cost at the time."
 
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