Difference between revisions of "20ma current loop to RS-232 conversion"
 (→My ASR hookup:  Added v1.1 schematic with my terminal strip numbers. wire legend nomenclature origins)  | 
				 (→Schematic 1.1:  added sub section headings)  | 
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[[File:RS-232 to ASR-33 Teletype Interface Schematic v1.1.jpg]]  | [[File:RS-232 to ASR-33 Teletype Interface Schematic v1.1.jpg]]  | ||
| + | ===Wiring legend===  | ||
<source lang="text">  | <source lang="text">  | ||
                                screw        wire              schematic  |                                 screw        wire              schematic  | ||
| Line 31: | Line 32: | ||
Received data return (-)         3          black           Data from Teletype -  | Received data return (-)         3          black           Data from Teletype -  | ||
</source>  | </source>  | ||
| − | + | ===Image details===  | |
[[File:My Altairclone TTY-RS232 Interface.png|600px]]  | [[File:My Altairclone TTY-RS232 Interface.png|600px]]  | ||
[[File:Teletype Model 33 ASR terminal block.png|600px]]  | [[File:Teletype Model 33 ASR terminal block.png|600px]]  | ||
Latest revision as of 09:36, 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.
Schematic 1.1
From the original schematic at altairclone I added ASR terminal strip location numbers.
Wiring legend
                               screw        wire              schematic
Signal                        terminal      color             connection
(Teletype 101 nomenclature)   (on ASR)      (mine)          (altair clone nomenclature)  
---------------------------------------------------------------------
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 -
