Difference between revisions of "20ma current loop to RS-232 conversion"
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[[File:TTY RS-232 Back.png|400px]]  | [[File:TTY RS-232 Back.png|400px]]  | ||
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* Helpful article, [http://www.vintagecomputer.net/teletype101.cfm Teletype 101] from vintagecomputer.net  | * Helpful article, [http://www.vintagecomputer.net/teletype101.cfm Teletype 101] from vintagecomputer.net  | ||
* Another circuit. From [[http://altairclone.com/teletype.htm Altairclone]] Specifically designed to fit in a Teletype model 33 using only a 12vdc wall wart for power.  | * Another circuit. From [[http://altairclone.com/teletype.htm Altairclone]] Specifically designed to fit in a Teletype model 33 using only a 12vdc wall wart for power.  | ||
Revision as of 08:43, 21 August 2015
Contents
20ma current loop <> RS-232 conversion
Vintage PCB
Dig this crazy circuit board man! Still in it's original packaging from Hobby World Electronics in Northridge California.
Additional Resources
- Helpful article, Teletype 101 from vintagecomputer.net
 - Another circuit. From [Altairclone] Specifically designed to fit in a Teletype model 33 using only a 12vdc wall wart for power.
 - Another circuit I found referenced on the greenkeys email list
 
My ASR hookup
I built the circuit described above from the altairclone site. I found the Teletype 101 article helpful for identifying the proper terminal strip locations. The interface works. I set baud to 110, with 7 bits and 'mark' parity in TeraTerm on a windows 8 notebook with a Gigaware USB<> serial convereter.
Signal                      screw terminal          my wire color
---------------------------------------------------------------------
Transmitted data send (+)      7          orange
Transmitted data return (-)    6          brown
Received data send (+)         4          red
Received data return (-)       3          black