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Phones
PTT
  
T65-TDK →
  
T-65
Analogue desktop telephone set with dial

T65 was the standard analogue telephone set for the Public Switched Telephone Network (PSTN) in the Netherlands, introduced in 1965 by the Dutch PTT (now: KPN), as the successor to the old black bakelite telephones, such as the 1951 Ericsson and 1955 Heemaf. It was developed by PTT in cooperation with the German manufacturer Krone. Like its predecessors it was dial-operated.

Subscribers were never the owner of the device, as it could only be rented from the Dutch PTT. The letter 'T' in the model number means Tafel­toestel (table device). The basic model was grey and was made of unbreakable ABS plastic. It was designed by the German manufacturer Krone.

The device greatly resembles the standard table tele­phone set of the German Bundespost, the FeTAp-61, 1 that had been introduced in 1961. Not only are the basic colour and cream details very similar, the dimension are nearly identical. As a result, the handsets are interchangeable.
  
Standard grey T65 with dial

The T65 was in production from 1965 to 1987. Millions of units were manufactured by Ericsson, Heemaf, Standard Electric (later NSEM) and Krone. From 1974, the T65 was also available with DTMF push-buttons – known as the T65-TDK 2 – but these could not be used everywhere, as the switches in several parts of the Netherlands had not yet been swapped for DTMF ones. The wall-mount variant of the T65 was the W65, and a version for integration in a desk was known as I65.

  1. FeTAp = Fernsprech-Tisch-Apparat (telephone table device).
  2. TDK = Toon-Druktoets-Keuze (touch-tone dialling).

Standard grey T65 with dial
Front view
Handset off-hook
Bottom side
Model tag
Connections
T65 telephone converted with DTMF keypad
Circular DTMF until for replacing the old pulse dial
A
×
A
1 / 8
Standard grey T65 with dial
A
2 / 8
Front view
A
3 / 8
Handset off-hook
A
4 / 8
Bottom side
A
5 / 8
Model tag
A
6 / 8
Connections
A
7 / 8
T65 telephone converted with DTMF keypad
A
8 / 8
Circular DTMF until for replacing the old pulse dial

Models
  • T65
    Table model
  • W65
    Wall-mount version
  • I65
    Version for integration in a desk
  • S65
    Series Device (for local multi-extension setup)
  • T65-SE5
    Semi-Electronic system version
  • T65-LB
    Local Battery with inductor instead of dial
  • T65-TDK
    DTMF version
Options
  • Earth button
    Initially, the T65 was available with and without an Earth-button, that connected the A-wire of the telehone line briefly to ground, to pass a call to the (optional) PABX. From 1973 onwards, the earth-button was present on all T65 units.

  • Colour
    The initial colour was (green-ish) grey with a cream bottom, dial and other details. In the 1970s, the phone also became available in a variety of colours, including red, green, white, brown, blue and orange, some of which are very rare today.

  • Lock
    A lock could be added – in the front left corner – to block outgoing calls. It shorted the contacts of the dial, and incoming calls could be answered as usual. Despite the lock, outgoing calls were still possible by tapping the hook switch in the correct rythm.

  • Volume control
    Handsets were available with an integrated knurled knob, that could be used to adjust the volume of the additional built-in amplifier.

  • Microphone amplifier
    An additional microphone amplifier could be added for people with a soft voice. It had to be enabled with a small black slide switch at the rear of the handset. This option is rare.

  • Mute button
    Handsets were available with a push-button that disconnected the microphone as long as the button was depressed. It was located at the same place as the volume control (above). The green variant of this option was also used on the NATO KF 4-2 voice terminal.

  • Noise-cancelling microphone
    For use in noisy environments, such as aboard ships and in military bunkers, a special noice-cancelling microphone was available. It was fitted instead of the regular micro­phone and was slightly thicker.

  • TDK unit
    From 1974 onwards, a circular DTMF unit was available that could be used to convert existing T65 sets (and particularly the wall-mount W65 and the integrated I65) from pulse dialling to DTMF dialling. TDK means Toon-Druktoets-Keuze (touch tone dialling).

  • GDK unit
    This option was similar to the TDK unit above, but used a different dialling system based on DC voltages. It was used by some PABX units made by Philips, and is extremely rare. GDK means Gelijkstroom-Druktoets-Keuze (direct current push-button dialling) [3].
TDK unit
For the conversion of standard T65 telephone sets to touch-tone dialling, circular DTMF units were made by Ericsson. These were particularly useful for the W65 and I65 models, which were not available in a DTMF variant as standard.

It has the same form factor as the old interruptor (pulse) dial, so that it could be retrofitted to any existing T65, regardless the manafucturer.
  
T65 telephone converted with DTMF keypad


Interior
Disassembled T65
Interior
Dial removed
Dial mechanism
Interior after removing the dial
Bell and transformer
Earth switch
Hook switch
B
×
B
1 / 8
Disassembled T65
B
2 / 8
Interior
B
3 / 8
Dial removed
B
4 / 8
Dial mechanism
B
5 / 8
Interior after removing the dial
B
6 / 8
Bell and transformer
B
7 / 8
Earth switch
B
8 / 8
Hook switch

Connections
Line
  • Red
    a
    Line (A)
  • Blue
    b
    Line (B)
  • Green
    E
    Earth (ground)
  • Yellow
    EB
    Extra bell (strapped to b in wall socket)
Handset
  • Red
    T
    Speaker (1)
  • Blue
    T
    Speaker (2)
  • Yellow
    M
    Microphone (1)
  • Green
    M
    Micriphone (2)
Subscriber line
Below is the pinout of a Dutch analogue subscriber line, as endorsed by the (then) state monopolist PTT. This is the pinout when looking into the wall socket, which is the same as looking at the screw terminals inside the instrument's plug (shown here). When no external bell is connected, a wire strap should be placed in the wall socket, between the B and EB contacts.

  • a
    Subscriber line (A) red
  • b
    Subscriber line (B) blue
  • EB
    External bell (normally strapped to b) 1
  • GND
    Ground
  1. The (EB) terminal is normally strapped to (b) terminal inside the wall socket. It is removed when an external bell set is connected to these terminals. If the phone doesn't ring, check whether this strap is present.

Known manufacturers
  • Ericsson
  • Heemaf
  • ITT
  • Krone
  • Siemens
  • Standard Electric (later NSEM)
References
  1. Wikipedia, T65 telephone
    Retrieved March 2020.  Dutch version

  2. KPN, Van telegrafie tot Internet of Things
    Retrieved March 2020.

  3. dutchtelecom, T65, de telefoon van Nederland
    Retrieved March 2020.  Background information
Further information
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Crypto Museum. Created: Thursday 30 March 2017. Last changed: Friday, 06 August 2021 - 07:14 CET.
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