The Z565M is a neon-filled decadic display tube produced by RFT in East Germany and sometimes referred to as a “Register Tube”. Although it resembles a Dekatron, it lacks any kind of counting capability. Unlike Pixie tubes such as the ZM1050/Z550M, it also cannot be controlled using logic-level signals. Instead, it operates more like a regular Nixie tube.

It features ten wire-formed cathodes arranged in a circle around a common anode, with each cathode activated by connecting it to ground. When viewed from the front, the tube shows two empty holes between each cathode. In a full Dekatron tube, these positions would have been occupied by the transfer electrodes. To ensure consistent ignition regardless of ambient light or background radiation, the Z565M includes a small amount of radioactive material to improve the rate of spontaneous ionization of the neon gas.

The Z566M is a large Nixie tube manufactured by RFT. It is pin compatible with the ZM1040 but differs in design, featuring a flatter top and a top-evacuation design, though some earlier units were evacuated from the bottom. In some instances, Z566Ms have even been rebranded and sold as ZM1040s (see picture at the end of this page). A variant without the pre-applied red filter was marketed as the Z5660M.

The Z566M was primarily utilized in laboratory equipment such as voltmeters and frequency counters. Its large size also made it well-suited for devices designed for use in educational settings, such as schools. A Nixie tube featuring various symbols, designed to complement the Z566M/Z5660M, was marketed under the names Z567M and Z5670M.

English title: Notes on the use of indicator tubes

This document contains information on various East German display tubes and examines their respective areas of application as well as their advantages and disadvantages. In particular, the different operating modes of Nixie tubes are discussed. At the end of the document the technical data of some common Nixie tubes can be found.

The content of the booklet differs from that of the similarly titled “Hinweise zur Anwendung von Anzeigeröhren - Sonderausgabe 3/1968”.

English title: Notes on the use of indicator tubes - Special issue 3/1968

This document contains an excerpt from the magazine “radio und fernsehen” (“radio and television”), published in the GDR, which discusses the use of various East German display tubes, with a particular focus on the Z570M and Z870M. It was released by RFT in March 1968.

The content of the booklet differs from that of the similarly titled “Hinweise zur Anwendung von Anzeigeröhren”.