Australian Public Telephone


Name Bluephone
Maker  GPT
Date (Introduced in 1989)

Siemen's Diamond payphone (similar to Bluephone but with metal housing)

The bluephone has the ability to bar calls to certain numbers. They have features such as displaying the number of calls that have been made when the coin box is emptied. The construction is lightweight on these phones, they are intended to be used in supervised locations only.

The phone is opened using a bi-lock key. There is a hinge on the LHS of the phone and the front of the phone swings open to reveal the coin mechanism. These phones can be switched into owner mode etc if the key is used.

Bluephones are manufactured by GPT. The RS Components catalogue used to show some payphones very similar to the blue phone. BT in the UK use phones very similar to the bluephones. 

-text by Henry Titchen. Reproduced with generous permission of author.

Technical Specifications

The Siemens Diamond Payphone is a customer operated payphone for installation in semi-supervised locations. It provides a wide range of features whilst being simple to use and operate.


  • High reliability
  • Easy tariff change facility
  • Fraud resistant
  • Cash content displayed in owner mode
  • All models suitable for wall or desk mounting
  • One coin slot for all coins
  • Electronic coin validation for 4 different coins
  • Local, long-distance, international, free, barred and operator facilities
  • Follow-on call facility
  • Line powered. No mains required.
  • Self diagnosis of faults
  • Owner mode facility allows operation as a normal phone
  • Hearing aid facility. Fitted with an inductive coupled hearing aid adaptor
  • Sixteen character display for user guidance


Access to the mechanism compartment and cash container is via a single keyswitch. A third position on this keyswitch allows use of the equipment as an ordinary telephone.


Aluminium diecast


  • Width 245mm: Depth: 180mm
  • Height 310mm: Weight 5kg
  • Cash container capacity 1 litre

Operation Range:

0 to 45 degrees Celsius, 10 to 70% RH


Decadic or DTMF dialling. Payphone identity tone and credit expiry tone.


Called subscriber answer indicated by 50Hz or 12kHz meter pulses. Call charges are computed from exchange meter pulses and the displayed tariff.

Tariff Changing:

Pre-set by factory or changed by the owner from the keypad.

Coin Handling:

In-line escrow, capacity 4 coins. Coins are cashed as they are used, in the order in which they are inserted. Unused coins are returned.


A range of maintenance agreements is available including comprehensive "parts and labour" cover