Viscount 12 (Telephone No. 9521R)
Telephone 9521R (Viscount 12) is a Self Contained press button telephone similar in appearance to other Viscount Telephones but has a 15 button keypad. 

Key features:

  • Loop dialling only.
  • Earth recall only.
  • 12 number memory, each number may be up to 16 digits and is stored by holding down the 'MS' button, pressing the keypad button it is to be stored under (1-0, .....) and then keying the number to be stored.  Stored numbers are transmitted by pressing the `MR' button followed by the keypad button that the number is stored under.
  • Last (Stored) Number Redial, an enhanced version of Last number re-dial requiring users to press the `MS' button if they wish to enter the number they have just dialled into the Redial store.
    The Stored Redial number may subsequently be transmitted by pressing the 'MR' and then the `MS' button.
  • Notepad Memory, by pressing the 'N' button once, users may then use the keypad to enter a number into the 'Notepad' store whilst a call is in progress without sending pulses to line.  The Notepad Memory number may subsequently be transmitted by pressing `MR' and then the 'N' button.
  • Secrecy, transmission and reception are both cut off by holding down the button to provide secrecy.

Colours: Ice Grey and Beige

Additional Information

The Notepad and Redial stores can both store numbers of up to 20 digits, a tone will be heard in the receiver inset if attempts are made to enter longer numbers.

There is no facility for storing PBX access pauses in any of the stores in the Tele 9521R.  PABX users should therefore manually key any Exchange line access digits before attempting to send any stored numbers.  This also applies to the Last (stored) Number Redial facility which will automatically delete manually keyed access digits from it's store, preventing them from being sent out twice.

Incoming calls are signalled by a tone ringer with adjustable volume control.

Field of Use
Suitable for use on Phone Socket installations on DELs or PBXs with Loop-disconnect impulsing and Earth Loop recall facilities. The Tele 9521R is designed for use on 50 Volt-working lines.

The Tele 9521R has a Ringer Equivalence Number (REN) of 1.  Telephone instruments (BT and non BT supplied) are now required to be labelled with their REN so that users do not exceed the permitted maximum number of ringers in circuit.  A telephone with a REN of 1 has a ringer performance comparable to that of a standard instrument (Tele 8746G), the total REN value of all ringers connected at any time at an installation must not exceed 4.

The REN does not guarantee compatibility between ringers of different technology on the same installation.

The Telephone 9521R is supplied with a line cord terminated with a plug 431A for use in Phone Sockets.

Routine Maintenance

Functional testing, cord replacement, Microphone or Receiver Inset change or unit change out.  The Tele 9521R contains sensitive components and care must be taken not to touch these when changing the line cord.

Power Requirements
Telephones 9521R are line powered and require no external power supplies.  Line current is drawn whilst the instrument is "on Hook" to maintain stored number memory (see Line testing, below).  The telephone should be left connected to Line in normal use otherwise stored numbers will be lost after approximately 5 minutes "Off Line".

Batteries are not required for the normal operation of the Telephone 9521R but may be fitted to retain stored numbers if the telephone is likely to be disconnected from line.  Battery provision and replacement is the customers responsibility, AAA sized leak-proof Alkaline cells (2 off) are recommended.  Battery drain is typically 15 micro Amps off-line and 7 micro Amps on-line giving several years battery life.


Component   Item Code
Telephone 9521R, Ice Grey   87 0018
Telephone 9521R, Beige   87 0019
Cord Conn. 4/506, 3000mm Charcoal   51 2300
Cord Conn. 4/506, 3000mm Cream   51 2301
Microphone Inset 22A   43 6271
Receiver Inset 3V   43 6272

Line testing
The stored number memory facility of the Tele 9521R draws approximately 22 micro Amps line current at 50 Volts whilst the instrument is on-hook and may result in low resistance loop line-test conditions.

When off hook the electronic keypad and transmission circuitry may give high resistance telephone loop conditions as with other self contained press-button telephones.


BTE Consumer Products.

Taken from Maintenance Information No. 035 (July 1984)

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Last revised: February 12, 2023