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Puzzling the SSC Block

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Hey folks,

Thanks for answering my question about SSC versions. I'm glad to know 
they all work identically.

I'm not adept at reading schematics, but I am trying to puzzle out what 
the block does.

My test rig is an enhanced //e connected to a Raspberry Pi running 
tcpser. I am using ProTERM 3.1 configured for a Hayes SmartMODEM 2400. 
tcpser is running with few parameters, one specifying the baud (2400) 
and another that turns on all debugging statements. I think I 
understand that because there is no modem, there is no DCE. Both 
computers are DTE.

Yesterday during tests to see what works for BBS connectivity and not, 
I found two basic success scenarios.

1. With block pointed toward MODEM, you must introduce a Null adapter 
in-line (or use a Null Modem cable) in order for ProTERM to be able to 
speak to tcpser's modem emulator.

2. With block pointed toward TERMINAL, you can use a straight-through cable.

My understanding of a _basic_ null modem (gathered from here: 
http://digital.ni.com/public.nsf/allkb/1EE0DD8AF67922FA86256F720071DECF) 
is that the TX and RX lines are swapped. For example, with the block 
pointed toward modem and an adapter in-line, TX on the //e side is 
connected to RX on the Pi side.

I figure that since pointing the block at Modem means I have to put a 
Null Modem adapter in-line before the Pi and, in Terminal, I can use 
straight-through, the block must be performing at least some basic null 
adaptation (or connecting RX to TX elsewhere?)

Looking at the schematic (available here: 
ftp://ftp.apple.asimov.net/pub/apple_II/documentation/hardware/schematics/super_serial_card_050-0045-a_schematic.pdf) 
I see the pin-out of the block and the lines on the spot where the 
block is inserted.

I'm not entirely sure how to ask my questions. I am going to try, but I 
may need to ask in different ways.

I think that the image of the block shows the physical pin-out while 
the spot on the schematic shows the pinout of the socket that's most 
convenient for the drawing. In other words, if you were able to 
physically pop-out the block drawing and insert is on the socket space 
in the schematic, pins showing a connection between 1 & 2 in the block 
pin-out wouldn't connect 1 & 15 on the socket.

Is that correct?

If that's correct, then pins on the block drawing showing 1 & 2 
connected would connect Pin 1 of 1489 to CTS.

Is that correct?

If both of those questions mean that I understand what's happening on 
the schematic, then ... what happens when you rotate the block? Where 
the connections inside the block represented in the drawing as it 
exists on the schematic -- 1&2, 3&4, 15&16, 13&14 -- now become 5&6, 
7&8, 12&11, 10&9?

If the block is creating a null adaptation internally (or if this is 
happening elsewhere), where is this happening?

Another question: The block as it is drawn on the schematic is Modem? Terminal?

I realize it might be easier to say, "Lookit, don't worry about it! It 
is what it is," but I would like to understand what's happening if 
possible, even though I'm finding it quite mind-bending.

Cheers,

Mike Whalen 

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Thread

Puzzling the SSC Block ultramagnus_tcv <mikew@thecomputervalet.com> - 2016-10-09 10:39 -0500
  Re: Puzzling the SSC Block ultramagnus_tcv <mikew@thecomputervalet.com> - 2016-10-09 11:46 -0500
  Re: Puzzling the SSC Block roger.shimada@gmail.com - 2016-10-09 21:18 -0700
    Re: Puzzling the SSC Block ultramagnus_tcv <mikew@thecomputervalet.com> - 2016-10-10 08:16 -0500
      Re: Puzzling the SSC Block Michael J. Mahon <mjmahon@aol.com> - 2016-10-10 12:58 -0500
        Re: Puzzling the SSC Block ultramagnus_tcv <mikew@thecomputervalet.com> - 2016-10-11 18:52 -0500
          Re: Puzzling the SSC Block roger.shimada@gmail.com - 2016-10-11 17:47 -0700
            Re: Puzzling the SSC Block ultramagnus_tcv <mikew@thecomputervalet.com> - 2016-10-12 09:36 -0500
              Re: Puzzling the SSC Block David Schmenk <dschmenk@gmail.com> - 2016-10-12 09:00 -0700
            Re: Puzzling the SSC Block ultramagnus_tcv <mikew@thecomputervalet.com> - 2016-10-12 09:37 -0500
              Re: Puzzling the SSC Block roger.shimada@gmail.com - 2016-10-12 20:37 -0700
                Re: Puzzling the SSC Block ultramagnus_tcv <mikew@thecomputervalet.com> - 2016-10-13 21:01 -0500
                Re: Puzzling the SSC Block ultramagnus_tcv <mikew@thecomputervalet.com> - 2016-10-16 08:47 -0500
          Re: Puzzling the SSC Block David Schmidt <schmidtd@my-deja.com> - 2016-10-11 21:27 -0400
            Re: Puzzling the SSC Block ultramagnus_tcv <mikew@thecomputervalet.com> - 2016-10-12 09:31 -0500
              Re: Puzzling the SSC Block David Schmidt <schmidtd@my-deja.com> - 2016-10-12 11:27 -0400
          Re: Puzzling the SSC Block Michael J. Mahon <mjmahon@aol.com> - 2016-10-12 01:18 -0500
            Re: Puzzling the SSC Block ultramagnus_tcv <mikew@thecomputervalet.com> - 2016-10-12 09:39 -0500
    Re: Puzzling the SSC Block ultramagnus_tcv <mikew@thecomputervalet.com> - 2016-10-10 08:26 -0500

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