Introduced in 1977 as a special phone for the Jubilee year.  In 1978 the telephone was then marketed as the "Compact Telephone" (Telephone No. 776) and was available in the colours, Blue, Light Grey and Brown.

3 Internal
Issue 1, Mar 1977

TELEPHONE No. 2/SA4271-1
"Compact Telephone: Jubilee Year Version"

This Instruction describes the Telephone No. 2/SA4271-1 which is a new style telephone, marketed as the "Compact Telephone: Jubilee Year Version".

Fitted with a Bell On/Off switch and a blank switch

 The telephone instrument, in dark blue, and bell unit in dove white, are separate items (Telephone No. 2/SA4271 and Bell Unit SA4271) but are issued from stock connected together by an extensible cord to form the Telephone No. 2/SA4271-1. Exceptionally, with the addition of a suitable block terminal to terminate the telephone cord, the telephone and bell unit maybe sited in different locations and interconnected by internal cable. The telephone can be converted to a wall type instrument by using a dark blue Bracket Telephone 1/D93235. The telephone and bell unit consist of a number of moulded parts secured mainly by snap action locking tabs. Screw fixing of parts and components is kept to a minimum. The circuit of the telephone and bell unit is of the 700 type and printed wiring boards are used to mount and connect the components. The transmission components and circuitry make the telephone suitable for use on local lines that have a line loss of not greater than 10 dB at 1600 Hz. (1000 ohms signalling).

The Bell Unit SA4271 in some cases may have a suitable termination for dropwire in addition to terminations for internal cable, thus avoiding the need for a separate terminal block; dimensions are less than existing bellsets permitting the unit to be mounted within the majority of window alcoves, etc. It is a clip-on fit to a wall plate which can be screw fixed to a flat surface, conduit box, or with the addition of angle brackets, to skirting boards or wooden window sills. When used on Plan 4 installations can be fitted with a jack into which can be plugged a portable telephone. It can be mounted within a wall bracket which also provides a secure shelf for the telephone. When mounted within the wall bracket the bell unit can also be provided with a jack.

The Telephone No. 2/SA4271 is of smaller dimension than existing 700 type instruments and will fit in narrower window ledges and recesses than existing telephone apparatus. It has a carrying handle and an extensible cord that will extend to approximately 3 metres length. There is provision for add-on switches to control the bell and also provide call exchange and operator recall conditions when required. An auxiliary gravity micro-switch may also be fitted.

The telephone and bell unit can be used on exclusive or shared service lines either as:-

  • direct exchange line,

  • main or extension of a Plan 1A installation,

  • at a Plan 4 installation,

  • direct PBX extension, internal or external.

  • The compact telephone maybe used with standard 700 type telephones on a Plan 1A, or a Plan 1A and Plan 4 combination. However, it is not permissible to use both compact and standard 700 type telephones as portable instruments on the same Plan 4 installation, as the plug and the jack wiring for each model is different.

The bell unit cover (Part 1/DCO/760) is a snap action fit to two sprung lugs formed on the bell unit base. The cover can be removed by inserting the tip of a small screw driver through the sound opening slots located at each end of the cover just sufficient to disengage the sprung lugs from the locking projections formed on the inside of the cover. The cover can then be lifted off the bell unit base.

The bell unit base (Part 1/DBA/209) provides a mounting for a Bell No. 79A, a printed wiring board (Part 1/DWI/311), which includes a 1.8 micro-farad capacitor, and an instrument cord anchor block (Part 1/DBL/122), or alternatively a Jack No. 136A. There are two groups of terminals. One has seven terminals, located around the instrument cord anchor block, suitable for terminating cord conductors and internal wiring, the other has three terminals, permanently connected to their equivalents in the seven terminal group, suitable for terminating dropwire. NOT ALL bell units issued will have the three terminals for dropwire connection.

Telephone No. 2/SA4271 fitted on the wall mounting bracket
The Bellset is fitted inside the lower part of the bracket

The telephone cover is secured by two projections, formed on the front edge of the cover, engaging in angled slots formed in the base moulding immediately below and to either side of the dial, and a single retaining screw adjacent to the rear edge of the base. To remove the cover the captive retaining screw, which is accessible from under the telephone, must first be disengaged. The instrument cover should then be lifted upwards and forwards until it clears the bottom edge of the dial, the front of the cover can then be lifted upwards and rotated towards the rear, clear of the telephone base. To replace the cover present it to the telephone so that the dial aperture passes over the dial. The two projections on the cover will engage and locate with the angled slots in the base, press the rear of the cover down onto the base and secure with the retaining screw.

Dial-Centre Label
In place of the normal dial centre label Factories Division will fit THE EMBLEM OF THE QUEEN'S SILVER JUBILEE. Two dial centres were produced, the English crown pictured on the left and the Scottish crown on the right. Dialling information for the customer is provided by fixing a standard self contained keyphone label between the switchhooks of the Telephone No. 2/SA4271. This label will be held in place and protected by a transparent plastic clip.

A Dial, Automatic No. 21 is secured to the base of the telephone by a two part retaining strap which is tensioned by a clamping screw. The tips of the two parts of the retaining strap are stepped and engage in two slots formed in the base moulding. To remove the dial from the base loosen the clamp screw and move the dial clear of the retaining straps, it is not necessary to disengage the retaining straps from the base moulding. To refit the dial locate it in position on the base. rotate the dial until the finger stop is positioned between the two vertical ribs formed on the base to the right of centre and tighten the clamping screw.

A Printed Circuit Board (Telephone Unit D93240) mounting the telephone circuit components, is mounted below the cradle lever and behind the dial; it is secured to the base moulding by a single fixing screw passing through the printed board. The regulator is an integral part of the telephone circuit and no provision is made for it to be rendered inoperative. A microswitch is mounted on the board and provides the changeover and make gravity switch contact units. Provision is also made for the handset, dial and Instrument cords to be screw terminated on the printed board.

The Cradle Lever is pivoted by knife edges bearing in V shaped sockets, formed in the base moulding, positioned either side of the dial. Coil restoring and retaining springs are attached to the cradle lever adjacent to the knife edges and anchored in the base moulding. A flat surface is formed on the under-side of the cradle lever and presses directly upon the gravity micro-switch operating button. When the hand set is in the 'on-hook' position the button of the gravity micro-switch is pressed fully into the switch housing so that the cradle lever rests upon the top surface of the micro-switch case.

A 'Linesman's Latch' in the form of a small segment with an extended lever is pivoted on a pin formed on the right-hand side of the cradle lever (when the telephone is viewed from the front). To engage the latch the lever should be pulled gently upwards until its movement is arrested by its forward stop. Check that the cradle lever rests on the top of the micro-switch case, the gravity switch will now be in the 'on-hook' position. To release the latch depress the lever fully. If the telephone cover is replaced when the latch is in the ton-hook' position, the cover will depress the lever thus releasing the latch.

The Bell Unit SA4271 must never be secured directly to a wall or other flat surface. To mount the Bell Unit SA4271 it is first necessary to secure the mounting plate (Part 1/DPL/2253), which is included with each Telephone 2/SA4271-1, or bell unit, to the surface upon which the Bell Unit SA4271 is to be mounted. To, release the mounting plate from the bell unit the bell unit cover must be removed as described above. The preferred method of mounting the bell unit is with the bell gongs uppermost, but where there is limited space the bell unit maybe fitted with the bell gongs facing either to the left or right. The bell unit MUST NOT be fitted with the bell gongs facing downwards.

The mounting plate has a variety of slots allowing various fixings; it may be by two Round Read screws secured to a conduit box (screws aligned horizontally or vertically), a wood backboard or fixture or a hard wall surface by plugged screw fixing.

It can be secured to a plaster or other soft wall surface by three No. 8 roundhead wood screws. By using the 4BA screws supplied, it can be fitted to an angled adapter (Part 1/DBR/686) which permits edge mounting to a window frame or similar structure. It can also be fitted, using the 4BA screws supplied, to an extension bracket (Part 1/DBR/687) which permits fitting to a skirting board, but positioned above the board, thus avoiding damage from vacuum cleaners or sweeping brushes.

The mounting plate has two slots stamped out of one of its long sides. The bell unit is a slide fit to the mounting plate and is locked in position by the cover overlapping the edge of the mounting plate in which these slots are stamped. For the purpose of explanation this edge is considered to be the bottom edge of the mounting plate and the fixing procedure is as follows:-

Remove the bell unit cover and release the mounting plate.

The mounting plate must be positioned, before fixing, so that there is a minimum gap of approximately 25 mm (1 inch) between the top and side edges of the mounting plate and any angle wall, window frame, or other obstruction. This gap is necessary to permit the bell unit to be engaged with the mounting plate before it is slid into its final position..

Secure the mounting plate to the wall or flat surface with the previously described edge at the bottom. Any of the slots stamped in the mounting plate may be used for the screw fixing.

There are two methods of gaining entry to the bell unit for cables, one for internally run cables the other providing direct access for drop wire cable.

Internal cable is fed into the bell unit through the hole below the instrument cord anchor block fixing screw, viewed with the bell unit gongs uppermost, which will align with the correct slot in the bottom edge of the mounting plate when the bell unit is slid into its final position. The cable is then terminated on the group of seven screw terminals. When the mounting plate is secured to a conduit box the internal cable may be passed through any of the empty slots in the mounting plate, except the two slots with flanges if a Bracket Telephone 1/D93235 is to be fitted.

The bell units that have been specially manufactured for the Jubilee Year Version of the Compact Telephone DO NOT have the three terminals for direct connection of drop-wire. BUT there are existing stocks of earlier manufactured bell units containing these three terminals, and if they are issued and the position for the bell unit in the Customer's premises is suitable for direct connection of drop-wire, the procedure can then be as follows:-

Slide the bell unit on to the mounting plate. Run the drop-wire to the bottom right hand corner of the bell unit and then feed upwards to terminate on the special drop-wire terminals. The drop-wire must NOT be wrapped around the screw terminals but after removal of the insulation be fed direct into the clamp device and secured by screwing down. Check that a firm connection has been made. Ensure that the cable is secured so that it does not obstruct the bell unit cover when it is replaced.

Having run and terminated either internal or external type cable make sure that the bell unit is correctly aligned on the mounting plate, and then replace the bell unit cover.

Two brackets are available to permit the bell unit and its mounting plate to be provided in a variety of situations that would otherwise require wall plugging, each is supplied complete with two 4BA screws.

Part 1/DBR/686 is an angle bracket allowing the mounting plate to be secured at a right angle to a window sill, etc. Two holes for suitable wood screws are provided in its narrowest side for securing it to the window sill. After securing, the Part 1/DPL/2253 (mounting plate) should be screwed to the widest side of the angle bracket with the two 4BA screws. Any two of the three tapped holes may be used depending upon the position required for the bell unit.

Part 1/DBR/687 is an extension bracket which is secured to a skirting board but has a fixing for the mounting plate that positions the bell unit above the skirting board. The extension bracket is a flat plate with a double right angle formed across the middle. One half of the bracket has three clearance holes for wood screws whilst the other part has three tapped holes for securing the Part 1/DPL/2253 (mounting plate). Secure the extension bracket to the skirting board with suitable wood screws so that the double right angle across the middle of the bracket positions the upper half of the bracket close to the wall. The mounting plate can now be secured to the extension bracket, with the two 4BA screws using either of the three tapped holes, depending upon the position required for the bell unit.


Call Exchange or Recall Switch
A composite non-locking switch and lever, titled a Switch No. 30A-1, can be provided on the right hand front edge of the telephone base so that the lever, which is marked CALL, protrudes under the front edge of the telephone case. The Switch No. 30A-1 and a dummy switch (Part 1/DLE/85) which is fixed to the left hand front edge of the telephone to maintain an aesthetic balance, are packed together and should be requisitioned as a Switch No. 30A-2. Applying upwards pressure to the front of the plate will disengage the plate and permit removal. The Switch No. 30A-1 is held in position by the front bottom edge of the switch case engaging under a slotted projection in the telephone base and a rounded projection on the back of the switch case engaging a sprung lug formed at the base of the dial clamp mounting. To fit the switch and dummy first remove the telephone case. Present the switch to the slot in the telephone base, with the lever tilted downwards, so that the bottom front edge of the switch case ban be engaged under the slotted projection. Apply pressure to the rear of the switch so that it rotates backwards towards its final position. The switch case will audibly snap into its final position. Check that the switch lever is free to operate and restore. The switch leads can now be connected to the appropriate terminals on the telephone circuit board, care being taken that the leads do not foul the cradle switch assembly or the linesman's latch. The dummy switch should be mounted on the left hand side of the base in a similar manner to that described above. To remove either the switch or the dummy, a small screwdriver should be engaged, from under the base, between the rounded projection on the rear of the switch or dummy case and the sprung lug formed on the telephone base. If a steady pressure is applied to the switch lever depressing it down and the screwdriver is twisted to disengage the switch or dummy body projection from the sprung lug, the switch or dummy can be pulled clear of the telephone base.

Bell On/Off Switch
A composite locking switch and lever, titled a Switch No. 30B-1, can be provided on the left hand front edge of the telephone base so that the lever, which is marked BELL, protrudes under the front edge of the telephone case. The Switch No. 30B-1 and a dummy switch (Part 2/DLE/85), which is fixed to the right hand front edge of the telephone, are packed together and should be requisitioned as a Switch No. 30B-2 (see picture above).

The switch and dummy should be provided in a similar manner to that described for the Switch No. 30A-2 (see picture above).

Auxiliary Gravity Switch Micro-switch
A Switch No. 19A-1, which is a micro-switch with mounting plates and fixing screw, can be secured to the side of the existing micro-switch on the telephone printed circuit board, to provide an auxiliary gravity change-over switch. The Switch No. 19A-1 should be clamped in position using the screw and tapped plate provided so that the existing micro- switch is sandwiched between the auxiliary gravity switch and clamping plate.

When the Switch 19A-1 has been secured and the leads connected to the telephone circuit, check that the leads do not foul the cradle lever and that the gravity micro-switches function correctly.

Bracket Telephone 1/D93235
This item is a moulded shelf assembly that can be mounted on the Part 1/DPL/2253, (which is used to mount the bell unit) to provide a container for the Bell Unit SA4271 and a rest for the Telephone No. 2/SA4271. When this bracket is used the bell unit MUST be mounted in it to provide rigidity. The fitting method for the bell unit in this case is described in the next paragraphs.

The Bracket Telephone 1/D93235 consists of three parts, the body moulding (Part 1/DBR/684), a lid (Part 1/DPL/2254) to cover the bell unit and provide a resting surface for the telephone, and a plug (Part 1/DPL/2255) which is used to fill a hole in the body moulding which provides access to a Jack No. 136A. This jack is only required for Plan 4 arrangements and is described later.

To install the Bracket Telephone 1/D93235 It is not necessary to disconnect the cord from either the telephone or the bell unit during installation in the wall mode. No attempt should be made to teed the telephone cord through the hole in the body moulding; this hole is for the insertion of a plug into the jack on a Plan 4 installation. Secure the mounting plate (Part 1/DPL/2253), which is packed with the Telephone SA4271-1, to the wall or other fixture. The mounting plate may be secured to a conduit box but it should be confirmed that the box is secured firmly enough to support the weight of the telephone, bell unit and telephone bracket. A clearance of at least 130 mm (5 inches) must be allowed above the mounting plate which must always be secured with the surface run cable entry slots at the bottom. The body moulding, with the flat back surface uppermost, should be raised above the mounting plate and slid downwards so that the web formed on the side of the moulding engage with the flanges on the side of the mounting plate and the bottom edges of the body moulding and mounting plate align. The moulding will now be held firmly, except for upwards movement, by the mounting plate.

Inside the body moulding, at the front, two hook projections are formed. adjacent to the edge of the large centre hole, and adjacent to the rear edge of the centre hole a clip is formed. The two hooks and the clip are used to secure the bell unit, minus cover, within the body moulding in a position with the components facing upwards, bell gongs at the front.

Remove the cover from the bell unit, this item is no longer required and should be returned to stock. Remove the screw securing the instrument cord anchor block to the bell unit base. Disengage the anchor block from the bell unit base, slight tilting of the anchor block will ease disengagement. Slide the cord grommet out of engagement with the anchor block and turn it so that the cord conductors emerging from the grommet are pointing upwards. Slide the grommet into re-engagement with the anchor block. Replace the anchor block within the bell unit base and secure with the fixing screw. The instrument cord now feeds downwards from the bell unit.

The plug (Part 1/DPL/2255) which is packed with the body moulding and the lid, should now be fitted into the hole in the right hand side of the body moulding. The plug should be fitted from the inside, with the flange inwards, and should be a close fit into the body.

The bell unit should now be fitted into the body moulding by the following manner. Hold the bell unit, minus cover, in the hand with the components facing upwards, bell gongs at the front. Turn the bell unit so that the edge containing the cord anchor block is at the bottom. Rotate the bell unit by approximately 45 degrees, clockwise or anti-clockwise, and feed it upwards right through the hole in the centre of the body moulding until it is above and clear of the moulding. Turn the bell unit until the components are facing upwards, bell gongs at the front, and gently place the bell unit inside the body moulding. Raise the rear edge of the bell unit and locate the front edge of the bell unit, adjacent to the bell gongs, under the two hooked projections formed in the body moulding. Check that the instrument cord falls clear of obstructions and then press the rear edge of the bell unit downwards until it is held by the body moulding clip.

Surface run internal cables can be fed into the bell unit, via the mounting plate, through the slot adjacent to the anchor block. Where special drop-wire terminals are provided surface run drop-wire or leading-in cable can be fed into the bell unit via a gap between the corner of the bell unit adjacent to the leading-in terminals and the body moulding. Cable running to the bell unit via a conduit box, to which the mounting plate is secured, can be fed into the bell unit via the slot adjacent to the anchor block.

On top of the lid (Part 1/DPL/2254) is a box formation; adjacent to it, on the rear edge, are two projections and on the front curved edge is formed a clip. To fit the lid, first ensure that the bell unit and body moulding are correctly located. Present the lid tilted downwards at an angle of approximately 45 degrees with the clip highest, to the moulding so that the two projections pass through the two slots in the back of the moulding. Press the front of the lid downwards until the clip engages. This secures the lid. The box formed on the top of the lid fits into a recess formed in the base of the telephone. If the telephone is now placed on the Bracket Telephone 1/D93235 it will be secure against accidental displacement.

Plan 4
These installations will be wired to diagram MS22016 for exclusive service, or MS22017 for shared service. All portable telephones must be of the compact type. Compact type telephones and 700 type telephones cannot be mixed when used as portable instruments. A Bell Unit SA427l is always fitted at the main station "intermediate" or "last". Stations can either be a standard Jack No. 95 or a Bell Unit SA4271 with Jack No. 136A. In all cases the existing circuit must be rewired to the appropriate MS diagram.

One portable compact telephone - wired to MS22016 or 22017

Two portable instruments or more - wired to MS22016 or 22017 but all portable instruments must be changed to the Compact type.

If only one Compact telephone is charged on the Advice Note then Sales Division must be contacted to negotiate the additional charge for the extra Compact telephones.

Jack No. 136A
To provide Plan 4 arrangements a Jack No. 136A can be fitted within a Bell Unit SA4271, whether it is wall mounted or contained within the Bracket Telephone 1/D93235. To fit the jack, first remove the bell unit cover, disconnect the instrument cord terminations and then remove the cord anchor block. Secure the Jack No. 136A in the position vacated by the anchor block, so that the plug can be inserted from the side of the bell unit, and terminate the flexible leads.

When the Bell unit is to be mounted within the Bracket Telephone 1/D93235 fit the Jack No. 136A to the bell unit before the bell unit is fitted into the bracket.

To allow insertion of the telephone plug, through the body moulding into the jack, the Part 1/DPL/2255 (plug) should be omitted. The recovered anchor block and Part 1/DPL/2255 should be returned to stock.

Plug 420 Grey-5A
To enable the Telephone 2/SA4271 to be used as a portable instrument on a Plan 4 arrangement, recover the instrument cord and replace it with a Plug 420 Grey-5A.

The recovered cord should be returned to stock.

TABLE 1 lists the items that will be delivered direct to Section Stocks from Factories Division.



Telephone No. 2/SA4271-1
Bracket Telephone No. 1/D93235
Bell Unit SA4271
Jack No. 136A
Plug No. 420 Grey-5A
Switch No. 30A-2
Switch No. 30B-2
Part l/DBR 686
Part l/DBE 687

Release Form A2827 (Demands for Non-Working Stock) should be used to obtain the above stores items from Section Stocks.

Stores Recovery
Normal STOP-START procedure is to be used and any recovery items should go via local wipe-up to become area maintenance holdings. Unsuitable items should be returned to Supplies Division as miscellaneous scrap.

Bell unit covers made spare when Bracket Telephone 1/D93235s are used should be returned to Section Stocks for maintenance spares.

Instrument cords recovered when Plug No. 420 Grey-5A axe used should also be returned to Section Stocks.

Shift and Change
The customer on moving will be allowed to take the Telephone No. 2/SA4271-1 with them to their new address. In this case the Telephone No. 2/SA4271-1 should be recovered and replaced with a 700 type instrument. It will be necessary to rewire the circuit to the equivalent N diagram. The installation of the Telephone No. 2/SA4271-1 at the customers new premises will be undertaken by the Telephone Area engineering staff under the authority of an A/N.

A list of maintenance replacement parts is given in MAINTENANCE TI E5 B2771.

The following diagrams are available for Telephone 2/SA4271-1:-

MS 22013 - Connections for Exclusive Service, Shared Service, PBX Extension and details of add-on units.

MS 22015 - Shared Service

MS 22016 - Plan 4 Exclusive Service

MS 22017 - Shared Service

Additional information

The compact telephone was first introduced in 1977 as a limited edition in the colour 'Balmoral Blue' to mark the occasion of the Queens Silver Jubilee. This version was known as the Telephone No SA 2/SA 4271-1.

The Jubilee telephone was marketed in two versions, English and Scottish, the differences being the type of royal crest in the dial label centre.

The telephone was later made available as the `Compact' in a choice of three colours (Stone, blue or Brown). It was the first telephone aimed at the residential market. Its compact fore and aft dimensions allowed it to be sited on a narrow ledge such as a window sill. It required a separate Bellset which could also be mounted at skirting level or within a specially designed wall bracket, on which the telephone could be placed. It employed the standard Telephone No. 746 circuitry with a new ringer unit, the Uni-coil Bell No. 79 and a Dial, Automatic No. 21 that was a low inertia version. This ringer then became a component option for the Tele 746.

If the case will not clear the dial finger plate, then remove the finger plate and refit later.


Model Mark Blue Grey Brown Introduced Remarks
Tele SA/4271 Mk 1 y y y 1971 Field trial version
Tele SA 4271-1 Mk 1 y y y   Field trail version, combined with B/S SA4271
Tele 1/SA 4271 Mk 1 y y y   Field trial version, with Switch No. 30A-2
Tele 1/SA 4271-1 Mk 1 y y y   Field trial version, wired for shared service
Tele 2/SA 4271-1 Mk 1 y     1977 Jubilee version - Balmoral blue only

Click here for converting this telephone to plug and socket working.


BACK Home page BT/GPO Telephones Search the Site Glossary of Telecom Terminology Quick Find All Telephone Systems

Last revised: February 12, 2023