Fanuc PPR - Paper Tape Punch, Printer and Reader : Not quite working

[Martin Bishop]

Fred

You have a good measure of my problem.

As for my expertise: its 40 years since I left schoool with a PhD in Signal Processing, I'm currently designing with Xilinx Zynqs, and if the RS232 driver has to be pulled there is a Pace SX-80 on the bench in the workshop.

I have a pair of light boxes and a CRO on the job:
-	Modular Technology MT25-IV on the PPR side (first outing in 20+ years), 
-	BlackBox TS50A on the D-9 side, 
-	CRO on p2 & p3

The CRO can see codes (at 4800 baud) going to the unit, but nothing coming out - stuck at logical zero (-7.5 V).  Putty talks to the PPR - characters to punch, Xon starts reader, etc.  Putty etc also talks to other hardware, i.e. its been tested.

<quote> Sometimes devices, at either end of the cable, have unexpected requirements,that are not usual parts of the RS232 "standard". </quote>  That, essentially is my question, before I start chasing a hardware / driver issue.  Although, to date, I have drawn a blank.

Knitting, first the D25 with pins on the PPR's OEM cable (pin : C/I/O(wrt PPR) : color : presumed function):
1 - C - black - chassis ground
2 - I - yellow - TXD fr Pc to PPR (evidenced by lites / CRO)
3 - O - brown - RXD fr PPR to PC (evidenced by lites / -7v5 voltage)
4 - I - green - RTS
5 - O - yellow - CTS
6 - O - gray - DSR
7 - C - orange - signal gnd
8 - I - brown - DCD
20 - I - jumper (grey) to pin 8 - DTR 
Note no other pins, esp 9 13 18 the D-25 current loop pins; therefore unlikely to be either current loop serial or 8 bit parallel (and the volts are not TTL).

D-25 to D-9 knitting (D25(PPR) : Direction : D9(Pc/FTDI 232) : function):
7 -- 5 common gnd
2 <- 3 TxD from Pc to PPR
3 -> 2 RxD from PPR to Pc
4 <- 7 RTS from Pc to PPR
5 -> 8 CTS from PPR to Pc
6 -> 6 & 1 DSR from PPR to Pc (DSR & DCD)
8 & 20 <- 4 DCD & DTR from Pc (DTR) to PPR (DCD & DTR)
Note I'm well aware that RTS to RTS etc is not normative, however the volts tell another story; presume I have a pair of DTEs / DCEs

Equally the classic quick bodge terminal (D-25) end jumpers don't deliver a result:
4-5 RTS-CTS
6-8-20 DSR-DTR-DCD

Thanks for your interest in my problem, and motivating me to open / inspect the D-25.

Martin

-----Original Message-----
From: Fred Cisin [mailto:cisin at xenosoft.com] 
Sent: 10 April 2022 03:06
To: Eric Moore <mooreericnyc at gmail.com>; General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
Cc: Martin Bishop <mjd.bishop at emeritus-solutions.com>
Subject: Re: Fanuc PPR - Paper Tape Punch, Printer and Reader : Not quite working

> to front panel keys.  However, nothing is emitted onto 232.  The D25 - 
> D-9 transition has all the RTS/CTS and DSR/DTR/DCD lines knitted 
> appropriately and indicating 'correctly' on blinkenlites.

I don't know anything about that specific setup, nor anaything aabout your personal expertise.

When you say "nothing on 232", is thatr per looking at the wires of the cable?  Or just not getting anything displayed by Putty?

When you say "knitted appropriately", since that is NOT referring to "as per the manual" (or is it?), have you checked all inputs and outputs?
Sometimes devices, at either end of the cable, have unexpected requirements,that are not usual parts of the RS232 "standard".

For example, I was once asked by the "Radio Shack Computer Center" to help them connect a Votrax to a Model 2 (for a blind customer).  They had tried all of the obvious commodity "null modems", etc.  I used a "matrix switch", but also had to solder one additional jumper for a pin that is not "normally" used for such things, and no obvious reason for being used. 
I no longer remember which pin; it was possibly #10 or #12, but it might just have been #22 ("ring indicator").  To avoid the bureaucratic administrative nonsense needed for them to pay me, I accepted a gift of a Model 2 Technical Reference manual as compensation.