Difference between revisions of "20ma current loop to RS-232 conversion"
 (→Other resources:  renamed to Additional)  | 
				 (→My ASR hookup:  Add schematic connection column to wire legend)  | 
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<source lang="text">  | <source lang="text">  | ||
| − | Signal                        | + |                              screw       my wire          schematic  | 
| + | Signal                      terminal      color           connection  | ||
---------------------------------------------------------------------  | ---------------------------------------------------------------------  | ||
| − | Transmitted data send (+)      7          orange  | + | Transmitted data send (+)      7          orange          Data to Teletype +  | 
| − | Transmitted data return (-)    6          brown  | + | Transmitted data return (-)    6          brown           Data to Teletype -  | 
| − | Received data send (+)         4          red  | + | Received data send (+)         4          red             Data from Teletype +  | 
| − | Received data return (-)       3          black  | + | Received data return (-)       3          black           Data from Teletype -  | 
</source>  | </source>  | ||
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[[Category:Various]]  | [[Category:Various]]  | ||
[[Category:Teletype]]  | [[Category:Teletype]]  | ||
| + | [[Category:Operational]]  | ||
Revision as of 09:08, 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.
                             screw       my wire          schematic
Signal                      terminal      color           connection
---------------------------------------------------------------------
Transmitted data send (+)      7          orange          Data to Teletype +
Transmitted data return (-)    6          brown           Data to Teletype -
Received data send (+)         4          red             Data from Teletype +
Received data return (-)       3          black           Data from Teletype -