3 Internal
ISSUE 3, MAY 1977

TELEPHONE 706.., 706R..., 710.., and 711..,
746.., 746R.., 740... and 741 ...
Provision on DELs, PBX Extensions and Extension Plans

This Instruction briefly describes the above Telephones, and lists the types of installations for which they are technically suitable. Telephones 746, 740 and 741 supersede the 706, 710 and 711 respectively, but there are some situations where the earlier instruments must still be used.

The Telephone 706... is described in B1001, the Telephones 706R... and 746R... are described in B1035, and the Telephone 710... in B1003. The Telephone 711... is the comparable wall mounted instrument and is described in B1004. The Telephone 746... and 740... are described in B1020, and the Telephone 741... in B1025.

A press-button which operates a single change over (microswitch) may be fitted in Telephones 706... and 711... UP to four press-buttons each operating up to four change over springset units may be fitted in Telephones 710... and 711... The Telephone 746... can accept one or two press buttons, each operating a single change over microswitch or multi contact spring set. The 740...and 741... can accept similar additional spring sets to the Telephones 710...and 711... respectively.

With the addition of auxiliary apparatus as specified in relevant diagrams the Telephones 706... 710... and 711 ... are suitable for use on DELs (exclusive and shared), PBX extensions and extension plan installations. The Telephones 746..., 740... and 741 ... are also suitable for these applications, but no pro- vision is made for the removal of the dial and regulator from circuit. The basic diagrams referring to the telephones and auxiliary apparatus are listed below:-

Index to N Dgms - N001
Telephone No 706 and 706R - N806
Regulator No 1 and No 1A - N801
Auxiliary units for Telephone No 706 - N808
Press-buttons for Telephone No 706 - N809
Telephone No 710 - N810
Telephone No 711 - N811
Telephone No 740 - N840
Telephone No 741 - N841
Telephones No 746 and 746R... - N846
Auxiliary units for Telephones No 710, 711, 740, 741 and 746 - N848
Press-buttons for Telephones No 710, 711, 740, 741 AND 746 - N849
Table of equivalent add-on units for Telephones 706, 710, 711, 740, 746 - N4700

(i) Telephone 706... is suitable for use when not more than one press- button is required. For shared service working the dummy press-button should be removed and the separate items:- Switch No. 5A-3, Thermistor No. 1A-1 and Part No. 4/DBU/263 (Colour) - fitted.

(ii) Telephone 710... Shared-service facilities can also be provided with Telephone 710... by fitting Switch No 5A-4 and Thermistor No 1A-1, with a press-button Part 22/DBU/260. The majority of shared service installations where a 710... has previously been specified can now be met with a 746.

(iii) Telephone 711 ... similar to Telephone 706... using press button Part 2/DBU/266, but see also B1004 and Dgms N 811.

(iv) Telephone 746... is suitable for shared service when one or two buttons are required. The dummy press button should be removed and the following parts fitted:-

Button part 1/DBU/362 (full width)
2 Pins part 1/DPI/203
Switch No. 5A-4, fitted in the unmarked central position of the gantry
Thermistor No. 1A-1
Plunger part 1/DPL/1022

Where two buttons are needed, two parts .../DBU/363 are substituted for the 1/DBU/362, and the switches fitted in positions B and C on the gantry. One or two plungers may be needed, depending on, the types of switches fitted.

(v) The Telephone 740... may also be used on shared-service, where three or more buttons are required, or where buttons are to latch under gravity switch control etc.

As these circumstances are relatively rare, reference should be made to the relevant diagram and N 4700. The parts are fitted similarly to the description above for the Telephone 746... Note that Telephone 740... requires button parts .../DBU/372. See Dgm N 849.

(vi) Telephone 741... As for Telephone 711..., see also B1025 and Dgm N 841.

Recall of the operator is made possible on 2-wire PBX extensions or on PMBXs with C-wire signalling as follows:-

(i) Telephone 706R... is already equipped for use on PBX's with Earth Loop Recall, Dgm N 806 Fig 4 details how it may be converted for use on PBX's with C wire recall, using a Part 1/DSP/1252.

(ii) On Telephone No 706... by fitting Switch No 5A-3, Part No. 4/DBU/263 and Rectifier Element No. 205. See Dgm N 806. For C-wire signalling, Part 1/DSP/1252 is also required.

(iii) On Telephone 710... by fitting Switch No. 5A-4 and Part No. 28/DBU/260. For C-wire signalling, Part 1/DSP/1242 is also required.

(iv) Telephone 711... see B1004 and Dgm N 811.

(v) Telephone 746R... is already equipped for use on PBXs with Earth Loop Recall, Dgm N 846 details how it may be converted for use on PBXs with C- wire recall. Note that one button engraved "Recall" is a component of the 746R... but is not available separately.

(vi) Telephone 746 ... may also be used for recall, if a Telephone 746R... of the required colour is not available. A plain but-ton should be fitted.

(vii)Telephone 740 ... may also be used for operator recall, reference should be made to the relevant diagram for details.

(i) Telephone 706...

Where not more than one press button is needed Telephone No. 706 ... can be used. When a non-locking action is required a Switch No. 5A-3 and Part No. 3/DBU/263 (Colour) engraved PRESS are available. A locking action switch, when required, is provided by Switch No. 5A-3 and Part No. 3/DBU/264 (Colour) engraved ON-OFF. If it is essential to have some other wording, a requisition (A1097) for a Part No. 4/DBU/263 (Colour) or Part No. 4/DBU/264 (Colour), respectively, should be sent with an engraving schedule (A1098) to the Factories Dept.

Then an auxiliary unit is fitted in the telephone case, the displaced dummy button [Part No 2/DBU/258 (Colour)] should be stored within the telephone for subsequent refitting. It will usually be possible to secure the dummy button and its fixing spring (Part No. 1/DSP/506) to the gravity-switch frame with a piece or insulating tape.

The following parts can be fitted as required (see N diagram of extension plan for details):-

Lamp Signalling Unit No 1 or 2
Parts No 1/DSP/1233, No 1/DSP/1252 and No 1/DSP/1256 (gravity-switch spring-sets)
Adapters, Local-battery, No. 5 and No. 6
Part No. 2/DST/836 with No. 1/DBR/366 (6-way terminal strip and fixing bracket)
Buzzer 32C-1
Strip, Connection, No 155A (18-way)
Adapter Plan Set No 1

(ii) Telephone 746...

On auto systems only, the Telephone 746 ... may be used on extension plans, when one or two press-buttons are required.

Non locking buttons use Switch 5A-4 with a plunger part 1/DPL/1022 and a button part ... /DBU/362 with two pins 1/DPI/203, or two buttons Part ... /DBU/363 with one pin 1/DPI/203 for each button.

Locking buttons are associated with Switch 23... For further details see Dgms N 848 and N 849.

The following parts can be fitted as required (see N diagram of extension plan for details):-

Lamp Signalling Unit No. 1 or 2
Switches 19B-1 (1 c/o), 19C-1 (3 c/o), or 19D-1 (2 c/o) Add-on Gravity Switches. These will shortly be superseded by new switches of improved design, coded Switches 36A-1 (1 c/o), 36B-1 (2 c/o) and 36C-1 (3 c/o).
Two parts 2/DST/836 (additional terminals)
Strip Connection 155A (18-way)
Capacitor No. 7712-2 with clip No. 90
Buzzer 32C-3

Adaptors local battery cannot be fitted to Telephones 746 ...

(iii) Telephone 710 ...
When up to four press buttons are required for extension plan working a Telephone No. 710... may be used. The appropriate dummy buttons should be removed and replaced with Parts No. 22-42/DBU/260 (Colour) as required. See Dgm N 849. If suitable wording does not exist a requisition for a Part No. 21/DBU/260 (Colour) should be sent with an engraving schedule (A1098) to the Factories Dept. To fit the required spring-sets (shown on Dgm N 848) the dial should be removed, when the spring-sets can be mounted under their appropriate press-buttons in the telephone cover. The latch settings which are shown on Dgm N 848 determine whether the buttons are locking or non locking and whether or not the gravity switch will release locked buttons. If a press button is fitted solely to, release a locked press-button, its plunger must be supported by a Part No 1/DST/26.

If a press-button is required to remain locked irrespective or the pressing of other buttons or the replacement of the handset, e.g. to cut off the bell, Part No .../DBU/262 should be used. If it is essential to have a non-standard legend a requisition (A1097) for a Part No. 1/DBU/262 should be sent with an engraving schedule (A1098) to the Factories Dept.

Any displaced dummy buttons (Parts No. 2/DBU/261) may be stored within the telephone for subsequent refitting. It will usually be possible to secure the dummy press-buttons to the gravity-switch frame with a piece of insulating tape.

The following parts can be fitted as required (see N diagram of extn plan for details).

Parts No. 1/DSP/1242, 1/DSP/1255, 1/DSP/1258, 1/DSP/1261. (additional gravity-switch spring-sets)
Adaptor, Local-battery, No. 4
Lamp Fitting No. 16A
Part No. 2/DST/836 (additional terminals)
Strip, Connection, No. 155A (18-way)
Buzzer 32C-1
Capacitor, No. 7712-2 with Clip No. 90
Lamp Signalling Unit No. 1 or 2

When a Lamp Fitting No. 16A is used the telephone cover should be replaced by a Part No. 6/DCO/627 (Colour) which is fitted with two clear lamp opals.

(iv) Telephone 740 ...

May also be used for plan number arrangements only on Auto systems, where up to four buttons are required.

Cases where two buttons are needed without interlocking, should be provided by means of the Telephone 746.

Press buttons for use with the Telephone 740... are coded ... /DBU/372 and are illustrated on Dgm N 849.

The latch plate is adjusted in exactly the same way as for the Telephone 710.

Independent locking buttons on the Telephone 740... cannot be provided by means of "slide lock" buttons such as the ... /DBU/262. However, a single change-overlocking switch can be provided by means of a Switch 23A-1 with a normal button part ... /DBU/372, a two change-over action requires a Switch 23B-1.

The Telephone 740... can also accept the following additional parts:-
Switches 19B-1 (1 c/o), 19C-1 (3 c/o) or 19D-1 (2 c/o) (Add-On gravity switches)
(To be superseded by Switches 36A-1, 36C-1 and 36B-1 respectively)
Lamp Fitting No 16A
Two Parts 2/DST/836 (additional terminals)
Strip Connection No 155A (18-way)
Capacitor No 7712-2 with Clip No 90
Lamp Signalling Unit No 1 or No 2
Buzzer 32C-3

When Lamp Fittings No 16A are fitted, replace the cover with Part 5/DCO/723 which is fitted with two clear lamp opals.

Any displaced dummy buttons (.../DBU/375) should be stored within the Telephone. Note that these are of four differing patterns, stamped "A", "B", and "D" to ease identification.

Plugs No 420, Grey with Cords, Instrument, No 4/97AD, Grey, and Jacks No 95A, or Plugs No 505, Grey with Cords, Instrument, No 5/39AD, Grey and Jacks 96A should be used for these installations. It is not possible to use these plugs and jacks on local battery systems because six conductors would be required and the demand would not be sufficient to justify the introduction of 6-way plugs and jacks. Where available Plugs 612 and Jacks 64A may be used.

To suppress clicks on Plans 2, 10, 12A, 105 and 107, a Rectifier element No 205 is to be fitted in the receiver cavity of the handset and connected across the receiver inset. Rectifier element No 205 should also be fitted on other installations if complaints of acoustic shock are received. Note that Teles 740, 741 and 746 already have a click suppressor in the Telephone. A second one should not be fitted in the handset.

(a) EXTENSION PLANS 2, 2A, 4, 12A, 105, 105A, 107 AND 107A
Will be installed with 700-type instruments.

(b) EXTENSION PLANS 1, 1A, 8, 8A, 9 AND 10
On any one installation instruments must be either all pre 700-type. or all 700-type.

As the 700-type telephone may have insufficient stray field to operate aids, a small stock of Teles 328 has been retained to assist in overcoming these subscribers problems. Nothing in the foregoing paragraph should be interpreted as prohibiting this arrangement, but circuitry will have to be worked out locally.

When coin-collecting boxes are required on subscribers extension plan installations in STD areas Boxes. Coin-collecting, No 700 and 700-type telephones should be fitted. Telephones without coin-collecting boxes at other stations on the installation must be replaced by 700-type telephones. The apparatus to be fitted will be listed on the appropriate works instruction form. Where prepayment boxes are still in use, new work and maintenance must at present use the 200-type instruments previously specified. It is possible that the use of 700-type teles with non STD coinboxes may become standard at some time in the future, and if so, a TI will be issued in due course.

(a) BLOCKS TERMINAL NO 52A (COLOUR) are now being issued with all Telephones No. 706... 706R..., 746... and 746R... The colours of the terminal blocks match the handsets of the telephones with which they are supplied. The red and white conductors of the instrument cord and terminals BT5 and BT8 are always used for the line circuit.

(b) Three larger terminal blocks are available for use with Telephones No 706..., 706R..., 710..., 740..., 746..., 746R... and very occasionally with Telephone No 711... and 741...

Block Terminal No 35A - 12 terminals, two rows of six with link straps
Block Terminal No 36B - 12 terminals, double-sided i.e. top and underside Three link straps are provided and may be used to link terminals as required in three directions.
Block Terminal No 37B - 25 terminals, two rows of ten with five in a central row, double-sided, i.e. top and underside. Link straps of the type used on Block Terminal No 30 may be used from the side rows to the central terminals.

Terminal blocks and cords are not supplied with Telephones No 710... 711... 740... and 741...

Some of the auxiliary units and replaceable items are seldom used and the Supplies Divn hold small stocks only. Requisitions for stocks should be confined to the quantities required to maintain two months supply at the current or estimated rate of issue.

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Last revised: April 13, 2010