[GreenKeys] 20ma current loop for my Dad's KSR 33

[Jeff Albrecht]

Hi Clay,

I have an ASR 33 connected to an 88-SIOJP from Martin configured as 
current loop in an IMSAI. Works great.

I'm wanting to verify that I can connect to this TWX KSR with the same 
terminal strip connections.

For future convenience when I get around to using a vintage Imsai SIO 
configured as current loop by all means YES I'd love to have an image of 
your jumper settings and pinouts for the IMSAI SIO. Thank you so much.

Thanks! - Jeff




On 10/8/2019 3:57 PM, Clay Archer wrote:
>
> Most serial I/O boards from that era support current loop.  There is 
> no need to convert it to RS232.   I have my Imsai connected to my ASR 
> 33 with an Imsai SIO board with current loop.    I can provide jumper 
> settings and pinout if you need it.
>
> Clay
>
> *From:*greenkeys-bounces at mailman.qth.net 
> [mailto:greenkeys-bounces at mailman.qth.net] *On Behalf Of *Andy KN4UCL
> *Sent:* Tuesday, October 08, 2019 5:00 AM
> *To:* Jeff Albrecht
> *Cc:* Greenkeys
> *Subject:* Re: [GreenKeys] 20ma current loop for my Dad's KSR 33
>
> Jeff - good luck with your project! I don’t know if you are aware of 
> David Mcnaughton’s IMSAI 8080 esp32 Kit - but that night be a neat 
> step to add.
>
>
> On Oct 7, 2019, at 6:47 PM, Jeff Albrecht <jeffa at rodaw.com 
> <mailto:jeffa at rodaw.com>> wrote:
>
>     This was my Dad's. Wayne says it is a TWX machine. Dad had it
>     hooked up to an IMSAI ~ forty years ago, although all the details
>     of his connections that apparently were made in one of the two
>     connectors that look like they would be hooked up to a phone
>     system have been lost. I'm pretty sure it was via a IMSAI SIO. I
>     personally played Star Trek on it.
>
>     I'd like to connect Dad's KSR like I did with this ASR 33 I bought
>     several years ago and hooked it up as shown on my wiki page;
>     https://wiki.theretrowagon.com/wiki/20ma_current_loop_to_RS-232_conversion#Image_details
>     Theoretically should that wiring configuration work on Dad's KSR?
>     The numbered screw strip in the second image?
>
>     So I went to plug it into A/C to see how it did in Local mode. 2
>     of the 3 fuses (see last image) are labeled. The third that is
>     missing it's fuse is not labeled. Any idea what fuse value I
>     should place in there?
>
>     <iblofbbohjbalcec.png>
>
>     Inside the KSR show above.
>
>     <mbdgklbiklcakaab.png>
>
>     <kgdbcpbipclofnio.png>
>
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