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Santec GNT-4606
Universal paper tape reader/puncher

The GNT-4606 was the last model in a series of flexible paper-tape reader/punchers from Helioprint (later: Santec) in Denmark. It was the successor to the GNT-4601 and the GNT-4604 and is suitable for 5, 6, 7 and 8-level paper and maylar tape, for teleprinters and computers.

The GNT-4606 can be connected to any personal computer with an RS-232 serial port and can be operated at various speeds and data formats that are selectable with switches at the front panel and DIP-switches at the bottom. The machine is ideal for the creation of teleprinter demo-tapes, for the generation of One-Time Tapes (OTT) for mixer machines (i.e. tapes with random characters) and for making key tapes.

The image on the right shows a typical GNT-4606 that we found on Ebay in 2012. We have adapted this unit for demonstration purposes and are currently writing suitable software for it.
Santec GNT-4606

The GNT-4606 has been in production for many years and is still available from a number of suppliers today (2012). It has been (and still is) rather popular with the users of old CNC-machines. It was also used by governments for the creation and distribution of crypto keys.

Santec GNT-4606 Santec GNT-4606 with open tape compartment Santec GNT-4606 with open tape compartment Close-up of the tape compartment Control panel GNT-4606 with open tape reader Close-up of the optical tape reader Rear view of the GNT-4606, showing our DB9 modification.

Help required
For the creation of cipher tapes and demonstrations of historical cipher machines, we are always looking for blank paper tape rolls. Especially the 1" 8-level tapes are hard to get. They were used in the 1970s and 80s for storing programs on early computer generations, but have since been phased out. Until recently they were also popular in the CNC industry. If you have any surplus rolls, please consider donating them to Crypto Museum. Your help is much appreciated.

We are currently in the process of modifying the GNT-4606 for demonstration purposes. We would like to be able to create 8-level key tapes for various cipher machines and 5-level tapes for a number of our mixer machines. For this, we want to connect the GNT-4606 to a computer (PC).

First we had to establish a physical connection between the GNT-4606 and our computer. The RS-232 connector at the rear of the puncher is of the old DB25 standard and suitable cables to the DB9 connector on our PC were not available.

So we decided to add a DB9 female type socket to the empty space at the rear of the unit. On older models this space was used for another DB25 socket. The DB9 connector has been wired in parallel to the existing DB25 socket, in such a way that we can used a standard DB9 extension cable (male/female) for connection to our PC.
Rear view of the GNT-4606, showing our DB9 modification.

Development of the software is currently underway and we hope to be able to create suitable 5-level and 8-level tapes before long. We will keep you informed of our progress through this page.

  1. GNT Automatic A/S (Santec), GNT-4604 Brochure
    Retrieved June 2012 from WNC Supply in Phoenix (AZ, USA).

  2. ECMA, Standard EMCMA-10 for Data Interchange on Punched Tape
    2nd Edition. July 1970.
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Crypto Museum. Last changed: Thursday, 03 September 2015 - 22:54 CET.
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