Jon

The interface card on most of Fanuc's PTRs is 
https://www.emeritus-solutions.com/papertape/fanuc/A20B-0007-075D_FanucPtrLogic.pdf
 the SN7437are 5V TTL Buffers, not OC but when did manufacturers trouble with 
standards.  However, that is the 8 bit parallel output, you can find a toy P to 
S interface with foot pedal hold for it at 
https://www.emeritus-solutions.com/papertape/fanuc/FanucInterFace1.zip

The controller for a RtR transport is 
https://www.emeritus-solutions.com/papertape/fanuc/A20B-0004-0280&0270_RtrPtrLogic.PDF
 the CNT3 input pins are the somewhat open questions.  And, while there is a 
little status feedback, on CN3, there is no dedicated handshake line.  Also, 
there are rewind, stop and hold command lines.  It is the usage of this 
interface, especially in the context of the larger CNC controller (on a Fanuc 
Mill / Lathe) which I seek.

The best way forward is probably to interface the RtR to a "controller" and to 
experiment; the controller being a convenient SoC. 

From what you write, it sounds as though this interface, with the transport to 
manage, is rather more complex than the necessary BTR subset.

Martin

PS Are the AB manuals readily available ?  Even operations manuals are hens 
teeth for Fanuc

-----Original Message-----
From: Jon Elson via cctalk [mailto:[email protected]] 
Sent: 03 March 2026 00:01
To: [email protected]
Cc: Jon Elson <[email protected]>
Subject: [cctalk] Re: Operating system, on punch cards?

On 3/2/26 16:16, Martin Bishop via cctalk wrote:
>
> And, I would very much like information on the remote control interface ...  
> No manuals, no recollections, no anecdotes, ...  I have asked in CNC land.
>
RS-323 was the standard for paper tape readers on CNC machines. It was not a 5V 
logic level interface, but was compatible with open-collector drive TTL chips.

Quite simple, 8-bit parallel with read forward, read reverse and a handshake 
line.

MANY years ago I built a "BTR" (behind the reader) interface for an 
Allen-Bradley CNC control.

Jon

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