In many cases manufacturers and the military gave tubes designations which said nothing about their purpose (e.g., 1614).

Explanation of tube designation systems (in English)

See Mullard-Philips tube designation for details.

Russian receiver tube designation system (in Russian)

There is a different "loctal Lorenz" in the Mullard-Philips tube designation .

The Anglo-European Mullard-Philips tube designation does include tube use information in the designation.

The RETMA tube designation does not incorporate the purpose of each tube in the designation.

The American RETMA tube designation number for this tube is 6CA7.

The European Pro Electron semiconductor numbering system originated in a similar way from the older Mullard-Philips tube designation.

A system widely used in Europe known as the Mullard-Philips tube designation, also extended to transistors, uses a letter, followed by one or more further letters, and a number.

Most octal tubes following the widespread European designation system have penultimate digit "3" as in ECC34 (full details in the Mullard-Philips tube designation article).

Pro Electron took the popular European coding system in use from around 1934 for valves (tubes), i.e. the Mullard-Philips tube designation, and essentially re-allocated several of the rarely-used heater designations (first letter of the part number) for semiconductors.

The first semiconductor devices, such as the 1N23 Silicon point contact diode, were still designated in the old RMA tube designation system, where the "1" stood for "No filament/heater" and the "N" stood for "Crystal rectifier".

Earlier in the 20th century, the organization was known as JETEC, the Joint Electron Tube Engineering Council, and was responsible for assigning and coordinating RETMA tube designations to electron tubes (also called valves).

In common with all 'E' prefix tubes, using the Mullard-Philips tube designation, it has a heater voltage of 6.3V. It is capable, when used at its plate rating of 300 volts maximum, of producing 17 watts output in Class AB1 in push-pull configuration.