TELEPHONE No. 772 & 8772


The X-Press Callmaker is being introduced, on a trial basis. This is to test the market reaction to a multipurpose instrument, which offers call making and 'repeat last number' manually dialled facilities in addition to a normal Keyphone push-button dialling function.

The X-Press looks like the ordinary SC Keyphone but its black buttons give it a distinctive appearance. Two additional buttons - labelled T - for transmit - and P - for programme - form part of the 12 button keypad.

A full telephone number, of up to 18 digits, can be stored on each of the ten digit numbers. The T button will also store the last manually keyed number enabling it to 'repeat dialled' automatically, if required. A simple two button depression is all that is required for automatic calling or repeat dialling.

X-Press Callmaker will be available only in light ivory for the trial in Bristol and Glasgow later this year, but in a wider colour range on general introduction.

It should be possible to fit the X-Press wherever an ordinary Keyphone can be fitted. The stores, which can be easily programmed or changed by the customer, are retained electrically by battery current. The battery is continuously being charged from line current or from a local power source. Should the power source fail the stores will be retained for a reasonable period until the power source is restored.

A minor circuit adjustment will enable the X-Press to be used on loop-disconnect PABX's. The appropriate public exchange access digit will be programmed under the T button. This does mean limiting the callmaking and repeat facilities to public exchange numbers only. Most internal calls on PABXs require the depression of a few digits only and should not inhibit their use on PABX installations.

Following a successful market trial it is hoped to make the X-Press more widely available towards the end of 1978.

Source - Post Office Telecoms New Product Bulletin 2/77

The X-Press callmaker was introduced in 1978

How to replace the internal battery

Around 1981 the Telephone No. 772 became the Telephone No. 8772 when it was fitted with high impedance bells (4000 ohms) and new style cord.


TELECOMMUNICATIONS INSTRUCTION
C MARKETING INSTALLATION
3 Internal
B3027
Issue 3, Sept 1978

TELEPHONE No. 1/772
X-Press Callmaker

INTRODUCTION
This instruction describes and gives information on the 10 pulses per second self contained Keyphone based on the Telephone 764, with the additional facilities of 10 telephone number storage and repeat last manually Keyed number.

The instrument is coded Telephone 1/772. The 12 button Push Button Unit (PBU) comprises 10 digit buttons marked 1 to 0, one button marked T (for Transmit) and one button marked P (for Programme).

DESCRIPTION

  • The Telephone 1/772 case, handset and escutcheon plate are only available in Ivory and the push buttons are black with white characters.
  • The telephone can be used as a standard Keyphone and is issued wired for Exchange Line working.
  • The buttons marked P and T are used to provide the facilities of 10 telephone number storage and repeat last manually keyed number.
  • Any complete National or International telephone number can be stored under any of the 10 digit buttons.
  • The last manually keyed telephone number is automatically stored so that it may  be readily repeated.
  • For PABX working a strap within the Telephone 1/772 has to be changed. The Public Exchange Access Digit can then be programmed and is automatically transmitted on a single depression of the T button. With this circuit change it is not possible to store or repeat last manually keyed extension/interswitchboard numbers.
  • The electronic circuits are powered by a blue cased rechargeable nickel - 7.2 volt cadmium battery (BATTERY SECONDARY No. 23 - coloured blue) which is connected to the telephone by plug and socket.

BATTERY CHARGING
The battery may be charged from the line while the telephone is "on-hook", or from a Power Unit No. 53 where line charging is not possible see Diagram N872 for details. When the battery is line charge, a charge switching unit (CSU) is incorporated to disconnect the charging circuit during periods of line testing.

FIELD OF USE
With the addition of auxiliary apparatus as required the Telephone 1/772 is suitable for use on Exchange Lines (exclusive and shared), PBX extensions (with or without recall) and those extension plan installations which could otherwise be met by the provision of Telephone 746, except for the following:-

  • Extension Plan 4 with more than one keyphone.
  • Extension Plan 4 with subscriber controlled transfer.
  • In conjunction with Lamps Signalling Units Nos. 1 and 2.

If a Telephone 1/772 is required on an extension plan where pre-700 type telephones exist, other than on the extension plans 5, 5A, 7 and 7A using Bellset 20, 39 or 44, all earlier types of instrument must be replaced by 700 type.

DETAILS OF CHARGING ARRANGEMENTS

Charging over Exchange lines or 50v
PABX extension lines may be employed for one Telephone on Exclusive DEL, and Extensions Plans on the following:-

  • DEL
  • Plan 1A - Main or extension
  • Plan 4 - One portable keyphone only

Shared Service Lines and Extension Plans
Charging facilities are dependent upon the calling equipment used in the exchange.

  • Uniselector per line, 200 pt line finder, UAX and TXK calling equipment's allow line charging for one battery powered Keyphone (e.g. Telephone 764, Telephone 772) on each party.
  • 50 Pt line finder, TXE2 calling equipment restrict line charging to one Telephone 1/772 to one party only.

Subject to above, the following application may be met:-
Shared service exchange line Plan 1A - Main or extension Plan 4 - One portable keyphone only.

50v PABX Direct Extensions and Associated Extension Plans
Charging may be employed for not more than one battery powered Keyphone (e.g. Telephone 764, Telephone 772 per extension line) on the following:-

  • Direct extension
  • Plan 1A - Main or extension
  • Plan 4 - One portable keyphone only

Charging from Existing Local Power SUPPLY
This method should be adopted for:-

  • Main or Plans 105, 107, 105A and 107A; two additional connections are required to extend the 12 V supply from the plan-set N625 to the charging circuit of the telephone.
  • Charging from the switchboard 50v supply should be employed for the operating telephone of 2/..... switchboards, and from the 50v supply for the operating telephone associated with Key and Lamp Units.

Charging from Power Unit Provided for this Purpose
Except for those listed above, all other applications will require the provision of a power unit. In addition, a power unit must be provided in lieu of the line charging, when switching facilities are provided to divert the line from the telephone to other equipment. Power Unit 53 should be used with a maximum of 80 BATTERIES SECONDARY No. 23 charged from one power unit. However, it is recommended that no more than 10 batteries be charged from a single fused outlet. An instrument cord with extra conductors and a larger block terminal than that shown in the appropriate N diagrams may be require&.

AUXILIARY UNITS
Telephones 1/772 will accept the same auxiliary units as Telephone 746 (see Diagram N848) except Strip Connection 155A and Lamps Signalling Units Nos. 1 and 2. When Clip No. 90 is required it should be fitted in the normal position.

INSTALLATION AND TESTING

Installation Non PABX

  • For wiring information see Diagram N872. Fit and connect the BATTERY SECONDARY No. 23 to the instrument.
  • When a Power Unit 53 is required (Diagram N872 Tables 1 and 2 refer) it should be installed in accordance with C3 Q0020.
  • On the completion of testing ensure that the handset is replaced on the rest to prevent excessive battery drain. For the same reason a Plan 4 portable Telephone 1/772 should always be left plugged into the line socket.
  • The pulsing of Telephone 1/772 is identical to that of a normal dial telephone and can be tested for speed and ratio in the normal manner.

Testing Non PABX
Distinct testing operations are required to ensure that the Telephone 1/772 is functioning correctly to give the following facilities:-

  • Normal Keyphone Working.
  • Repeat Last Manually Keyed Number.
  • Store Programmed Numbers.
  • Send Programmed Numbers.

Normal Keyphone Working
Make sufficient test calls to ensure the correct pulsing out of all digit buttons. Replace handset.

Repeat Last Manually Keyed Number
To check that the last number keyed can be repeated: Lift the handset and on receipt of dial tone depress and release the T button twice.

Store a Programmed Number
Storage of a telephone number under a digit button is achieved by the following procedure:-

(i) Lift the handset and place to one side.

(ii) Depress and hold down the P button.

(iii) Depress and release the digit button under which the telephone number is to be stored.

(iv) Depress and release the digit buttons corresponding to the telephone number to be stored.

(v) Release the P button.

(vi) Replace the handset.

Send a Programmed Number
Check that the telephone number has been stored by sending it to line using the following operating procedure:-

(i) Lift the handset and wait for dial tone.

(ii) Depress and release the T button.

(iii) Depress and release the digit button under which the telephone number is stored.

The successful storage and transmission of one complete telephone number is sufficient to check the electronic circuitry.

To Erase a Stored Telephone Number
Carry out the following operations:-

(i) Lift the handset and place to one side.

(ii) Depress and hold down the P button.

(iii) Depress and release the digit button under which the telephone number to be erased is stored.

(iv) Release the P button.

(v) Replace the handset.

To Change a Stored Telephone Number
It is not necessary to carry out a separate erase operation as above. The new number is entered as above replacing the existing stored number.

Installation for PABX Working

Fit and connect the Battery Secondary No. 23 to the instrument and refer to Diagram N872 for wiring details; note that for PABX working the position of the RED-WHITE wire must be changed from T31 to T28. This will allow for the storage of a PABX ACCESS DIGIT which will be used in providing the facilities of:-

  • Store and Send Programmed Numbers
  • Repeat Last Manually Keyed Number

The stored PABX ACCESS DIGIT is NOT used for normal Keyphone working.

Programming also applies when PABX working.

Testing for PABX Working

Recommended Testing Order
It is recommended that the testing for PABX working is carried out in the following order.

(i) Normal Keyphone Working.

(ii) Programming the PABX Access Digit.

(iii) Repeat Last Manually Keyed Number.

(iv) Store a Telephone Number.

(v) Send a Stored Number.

(vi) Erase a Stored Number.

(vii) Change a Stored Number.

Normal Keyphone Working
Make sufficient test calls (internal extension and exchange line calls) to check the correct pulsing out of all digit buttons.

For exchange line calls proceed as follows:-

(i) Lift the handset.

(ii) On the receipt of PABX dial tone key in the appropriate PABX access digit.

(iii) When exchange dial tone is received Key in a suitable test number.

(iv) Replace handset on completion of call.

Programming the PABX Access Digit
The Telephone 1/772 can store the required PABX Access Digit (only a single digit) which is used with the sending of Stored Numbers and Repeating the Last Manually Keyed Number.

The access digit is programmed as follows:-

(i) Lift the handset and place to one side.

(ii) Depress and hold down the P button.

(iii) Depress and release the T button.

(iv) Depress and release the digit button corresponding to the PABX Access Digit to be stored.

(v) Release the P button.

(vi) Replace the handset.

The Programmed Access Digit should be left in store for future use by the customer and is used for testing the Telephone 1/772 facilities of:-

  • Repeat Last Manually Keyed Number.
  • Store Programmed Number.
  • Send Programmed Numbers.

Because the Access Digit will be transmitted when the T button is depressed these facilities are not available for internal extension calls.

Repeat Last Manually Keyed Number
To check this facility proceed as follows:-

(i) Make a test call (e.g. 9-1234).

(ii) Replace handset.

(iii) Lift handset and wait for PABX dial tone.

(iv) Depress and release the T button, which will transmit the Programmed PABX Access Digit (e.g. 9), and wait for exchange dial tone.

(v) Depress and release the T button once again which will transmit the test number in (i) omitting the PABX access digit (9) thereby only sending 1234.

(vi) Replace handset on completion of call.

Store a Programmed Number Omitting the PABX Access Digit
Store the telephone number by the method as above.

Extension telephone numbers CANNOT be stored.

Send a Programmed Number
Check that the telephone number has been stored by sending it to line using the following operating procedure:-

(i) Lift the handset and wait for PABX dial tone.

(ii) Depress and release the T button (The PABX Access Digit will be transmitted) and wait for exchange dial tone.

(iii) Depress and release the digit button under which the telephone number is stored.

(iv) Replace handset on completion of call.

Erase a Stored Telephone Number
Carry out the operations as for non PABX.

Change a Stored Telephone Number
Carry out the operations as for non PABX.

Change PABX Access Digit
Should it be necessary to change the PABX Access Digit carry out operations as for non PABX. The New Access Digit will automatically replace the Existing Access Digit.

Completion of Testing
On completion of testing (PABX and Non PABX) erase all stored test numbers but DO NOT erase the Programmed PABX Access Digit.

Ensure that the handset is replaced on the rest to prevent excessive battery drain.

CARRIER CIRCUITS
When Keyphones are required on either the physical or carrier circuits of 1 + 1 Carrier it will be necessary to provide a Power Unit.

Advice Notes should be checked by Distribution Officers before issue to installation staff in order that arrangements can be made for a power point to be available.

RECOVERY
Recovered instruments must be returned to Section Stock. Battery Secondary No. 23 should be removed from the instrument and handed to stores staff for recharging in Dispenser 4B.

Introduced in 1978.


POWER CIRCUIT STRAPS
To change between the different methods of battery charging, straps within the telephone must be moved.  The telephone is supplied with the Battery strapping set to Line charging.  The straps are set T26 - T27.

For 50v local power feed - remove strap from T26 - T27, strap across T27 - T28 and finally, move the yellow and green wires from the Press Button Unit (PBU) and connect to the PSU feed.
For 10v local power feed - remove strap from T26 - T27, strap across T28 - T29 and finally, move the yellow and green wires from the PBU and connect to the PSU feed.

CHARGING CHECK
Line charging

To check the charging circuit connect a milliameter in place of the strap T26 (-ve) and T27 (+ve).  With the handset on the rest a current of 2 - 3mA should flow after 30-100 seconds.  Replace strap after testing.

Charging by local PSU
To check the charging current connect a milliameter in place of the strap T27 (+ve) and T28 (-ve) for 10v PSU's or T29 (+ve) and T28 (-ve) for 50 v PSU's.  With the handset on the rest the current flow should be 2 - 3mA.  Replace strap after testing.


Additional information

ModelMarkGreyIvoryPBU NoIntroduced Remarks
Tele 772Mk 1yy55A/31/80 PYE/TMC Originally 1/772
 Mk 2yy55A/2  GEC Originally 2/772
Tele 772KMk 1yy55B/33/80 TMC fitted with subs dial lock
Tele 1/772Mk 1yy 11/76 PYE/TMC See Tele 772
Tele 2/772Mk 1 y 10/78 GEC See Tele 772
Tele 8772Mk 1yy55A/3  PYE/TMC
Tele 8772Mk 2yy55A/2  GEC

 

 
 
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Last revised: May 30, 2010

FM