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) | ||
| Line 20: | Line 20: | ||
| [[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 -






