C MARKETING INSTALLATION
ISSUE 3, MAY 1977
No's 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
No. 746, 740 and 741 supersede the Telephones No. 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 No. 706R... and 746R... are described in B1035, and the
Telephones No. 710... in B1003. The Telephones No. 711... is the comparable wall mounted instrument and is described in B1004. The
Telephones No. 746... and 740... are described in B1020, and the Telephones
No. 741... in B1025.
A press-button which operates a single change over (microswitch) may be fitted in
Telephones No. 706... and 711... UP to four press-buttons each operating up to four change over springset units may be fitted in
Telephones No. 710... and 711... The Telephones No. 746... can accept one or two press buttons, each operating a single change over microswitch or multi contact spring set. The
Telephones No. 740...and 741... can accept similar additional spring sets to the
Telephones No. 710...and 711... respectively.
With the addition of auxiliary apparatus as specified in relevant diagrams the
Telephones No. 706... 710... and 711 ... are suitable for use on DELs (exclusive and shared), PBX extensions and extension plan installations. The
Telephones No. 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 Diagrams - 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
No. 706, 710, 711, 740, 746 - N4700
(a) SHARED SERVICE (AUTO)
Telephones No. 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.
Telephones No. 710... Shared-service facilities can also be provided with
Telephones No. 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.
Telephones No. 711 ... similar to Telephone 706... using press button Part 2/DBU/266, but see also B1004 and Diagrams N 811.
Telephones No. 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
No. 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
No. 746... Note that Telephone No. 740... requires button parts .../DBU/372. See Dgm N 849.
No. 741... As for Telephone No. 711..., see also B1025 and Diagram N 841.
(b) PBX EXTENSIONS WITH RECALL FACILITY
Recall of the operator is made possible on 2-wire PBX extensions or on PMBXs with C-wire signalling as follows:-
No. 706R... is already equipped for use on PBX's with Earth Loop Recall, Diagram 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
No. 706... by fitting Switch No 5A-3, Part No. 4/DBU/263 and Rectifier Element No. 205. See Diagram N 806. For C-wire signalling, Part 1/DSP/1252 is also required.
(iii) On Telephone
No. 710... by fitting Switch No. 5A-4 and Part No. 28/DBU/260. For C-wire signalling, Part 1/DSP/1242 is also required.
No. 711... see B1004 and Diagram N 811.
(v) Telephone No. 746R... is already equipped for use on PBXs with Earth Loop Recall, Diagram 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.
No. 746 ... may also be used for recall, if a Telephone No. 746R... of the required colour is not available. A plain but-ton should be fitted.
No. 740 ... may also be used for operator recall, reference should be made to the relevant diagram for details.
(c) EXTENSION PLANS
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)
Strip, Connection, No. 155A (18-way)
Adapter Plan Set No. 1
On auto systems only, the Telephone No. 746 ... may be used on extension plans, when one or two press-buttons are required.
Non locking buttons use Switch
No. 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 Diagrams 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
No. 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
No. 36A-1 (1 c/o), 36B-1 (2 c/o) and No. 36C-1 (3 c/o).
Two parts 2/DST/836 (additional terminals).
No. 155A (18-way).
Capacitor No. 7712-2 with clip No. 90.
Buzzer No. 32C-3.
Adaptors local battery cannot be fitted to Telephones
No. 746 ...
(iii) Telephone No. 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 Diagram 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 Diagram 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 Diagram 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 extension
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).
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.
No. 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
Press buttons for use with the Telephone No. 740... are coded ... /DBU/372 and are illustrated on Diagram N 849.
The latch plate is adjusted in exactly the same way as for the Telephone
Independent locking buttons on the Telephone No. 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
No. 23A-1 with a normal button part ... /DBU/372, a two change-over action requires a Switch
The Telephone No. 740... can also accept the following additional parts:-
No. 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
No. 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.
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.
(d) EXTENSION PLAN 4 INSTALLATIONS
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
No. 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
No. 612 and Jacks 64A may be used.
(e) PREVENTION OF ACOUSTIC SHOCK
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 Telephone
No. 740, 741 and 746 already have a click suppressor in the Telephone. A second one should not be fitted in the handset.
INTERMIXING OF 700 TYPE AND EARLIER TELEPHONES
(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.
(c) SUBSCRIBERS USING INDUCTIVELY COUPLED HEARING AIDS
As the 700-type telephone may have insufficient stray field to operate aids, a small stock of Telephone
No. 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.
(d) EXTENSION PLANS WITH COIN-COLLECTING BOXES
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 telephones 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 Division 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.