So sanity check here. I’m pretty new to all of this and I had a question about voltage levels. The Blue SMiRF data sheet says it only puts out 5V levels, whereas RS-232 levels vary from plus or minus 3 upwards. The Blue SMiRF just connects to the Tx and Rx TTL lines on the SSC-32, so is there some sort of conversion circuitry there? Can anybody clear this up? Everybody says the tutorial works in a snap so I’m just kind of wondering how.
Whoa! check this out…
lynxmotion.net/viewtopic.php?t=2396
It’s a lot easier than you are thinking… 8)
Jim’s post is the best to look at.
Just make sure you don’t plug it into the shifted levels, or a pc.
The shifted levels for a pc are supposed to be 0-12V.
TTL is what you need, direct links.
Steve
no, active 1 is -12V active high is +12V
Yes, the RS-232 standard includes large swings in the signal voltages.
No, you don’t need to worry about it in this case.
The TX and RX jumper points on the SSC-32 are TTL-level tie-points that come after a conversion process.
Short-form answer:
The Blue SMiRF has connections for TTL-level serial.
The SSC-32 has connections for TTL-level serial.
Use a couple of wires to hook them up, and you’re in business - no worrying about signalling voltage levels as specified in the RS-232 standard.
Sorry, you’re right spacejunk, the levels are supposed to be -12 to +12V for RS232.
My bad 
Sorry for the confusion. No need to worry about them anyway natrix, seeing as you’re using TTL levels.
Steve