3 Internal
M 0035

Description and Installation

This instruction describes and details the installation of the Autodial No. 101A (Key Callmaker), which enables subscribers connected to Automatic exchanges or PABXs (not PABX 5 or 6) to call other frequently used numbers without the necessity of remembering or dialling the telephone number. To call other subscribers and in the event of mains failure, the normal telephone dial may be used. The Autodial cannot be used on shared service lines and House Exchange Systems and is not recommended for use on PMBX's.

The Autodial is a repertory dialler, giving a capacity of sixteen digits per address and thirty-two addresses. The operation of an address button allows a predetermined telephone number to be transmitted to line in the form of 10 pps loop/disconnect pulses. A simple amplifier and loudspeaker is provided to monitor the progress of calls and the handset of the associated telephone need only be lifted for conversation when the call has matured.

The addresses are stored on a translation field by means of wire connectors.

The items which comprise an Autodial No. 101A are a Key Unit No 1A, a Translator No. 1A, a Power Unit No. 86A, a Box Connection No. 6A, 200 Connectors No. 1001A, an Insertion Tag No. 1 and an Extractor No. 11.

The Key Unit No. 1A is a desk unit measuring 9 inches x 7 inches x 3 inches, and houses the thirty-two address buttons, a cancel button, an ON-OFF switch, a miniature loudspeaker, and two lamps, which indicate when the dialler is in use and when the power is on. The address buttons are arranged in four columns of eight and each button is provided with a paper designation label protected by a transparent plastic cap. When a button is operated it remains locked down while the autodial is controlling the call.

The Translator No. 1A is a wall-mounted unit measuring 18 inches x 10 inches x 4 inches and houses the autodial circuitry and the translation field. (Figure 2). It is connected to the Key Unit, via a Box Connection No. 6A, by a 41-wire cable. The power unit and the line are connected to the translator by two one-pair cables. The telephone is connected to it by a three-wire cable.

The Power Unit No. 86A is a wall mounted unit measuring 8 inches x 5 inches x 3 inches. It is mains operated and gives an approximate off-load DC voltage of 18 volts.

The Connectors No. 1001A are tag ended wires used for address programming and are supplied in four colours in units of 25.

The following items should be requisitioned:-

Translator No. 1A
Key Unit No. 1A
Power Unit No. 86A
Inserter Tag No. 1
Extractor No. 11
Connectors 1001A (Red)
Connectors 1001A (Blue)
Connectors 1001A (White)
Connectors 1001A (Green)
Box Connection No. 6A
Cable PVC No. 1 41W/6 lb. as required
Cable PVC No. 1 4W/6 lb. as required

A three-pin mains plug to suit the socket outlet provided by the subscriber and a 3-core mains cable should also be obtained.

Location and Mounting
The Box Connection No. 6A should be mounted such that, when the Connector No. 1046A is joined to it, the cord leads out naturally and allows the key unit to be positioned adjacent to the telephone. The Translator No. 1A should be wall mounted, in an upright position, at a comfortable working height and In a well-lit situation agreed by the subscriber and within a 30-yard cable run of the key unit. Cable runs of up to 60 yards may be used provided the subscriber Is satisfied that the level of reproduction in the monitor amplifier loudspeaker Is acceptable. Round Head No 6 wood screws at least 1 inch long should be used for mounting the translator.

The power unit should be mounted close to the translator. The DC output can be connected to the translator or the box connection as convenient.

Connection Details
To gain access to the terminals In the translator once the lid has been opened, the four screws from the extreme corners of the unit should be unscrewed allowing the terminal cover to be removed. Cables entering the translator should be clamped in position with the clamp provided.

  1. Power Unit Connections. Check that the mains-transformer Input is S trapped correctly for the local mains supply. Connect the power unit as shown In diagram N2310.
  2. Direct Exchange Line Connections. The Auto Dial should be connected as shown on diagram N2310.
  3. Connection to PABX Extension. The Autodial should be connected as shown on diagram N 2310 with the exception that the green conductor In the telephone cord should be transferred from the box connection terminal 50 to box connection terminal 48. The PABX recall earth should be connected to box connection terminal 48 and the telephone wired according to Diagram N 806 panel 4.
  4. Connection to Single Line Extension Plans. The Autodial should be connected directly to the exchange line as follows:-
    Disconnect the line pair from the extension-plan terminal block and connect it to the box connection terminals 54 and 56 as shown on diagram N 2310. The telephone shown on diagram N 2310 is not required and the box connection terminals 50 and 52 should be connected to the terminals on the extension plan terminal block from which the line pair was removed.

    The selected telephone of the extension plan may now be used with the Autodial. Other connections should be made according to diagram N 2310.
    If sufficient spare terminals exist in the box connection all the extension-plan wiring should be transferred to these terminals allowing the original terminal block to be recovered. When this is done a local record should be made to assist - subsequent maintenance activities.

    It should be noted that in the case of a Plan 105 or Plan 107 the Autodial may be connected at the extension to the incoming pair to the telephone as if it were the line pair, according to the above principles.
  5. Connection to Extension Plans with more than one Line. The Autodial can only be connected to one selected exchange line and should be connected according to the wiring principles described in paragraph (d) above.

Translator Permanent Straps
Two rows of tags in the top left hand corner of the lower circuit board of the translator are accessible when the terminal cover is removed. The tags should be checked that they are strapped as shown on diagram N 2310. The 'LEVEL' tag is normally strapped to the "DIGIT 91 tag thus allowing an access digit 191 followed by a long inter-digital pause to be transmitted when required at PABXS. Should the access digit required be of a value other than 191 then the strap should be moved to the appropriate digit digit tag.

The 'XCH LINK' renders the access digit preceding the ISD code ineffective and should only be removed when the Autodial is connected to a PABX extension.

Address Connections
The translation field has thirty-two groups of thirteen tags. One tag is labelled "Access' and the remainder are numbered 1 to 12. There are fourteen slotted bars between the tag groups, representing digits 1 to 0, EXCH, ISD, STOP and one spare bar. The appropriate tags of each address should be connected to the digit bars by use of Connectors No 1001A. The connector tag should be located in the end of the Inserter Tag No 1, with the connector wire laying in the groove in the shank of the tool. The tag can then be pressed onto the appropriate address tag. This process should be repeated with the other end of the connector so that it is located horizontally in a slot on the required digit bar.

Should it be necessary to remove a connector, the Extractor No 11 should be hooked into that part of the tag - immediately below the crimp and gently pulled off the terminal. The connectors are sup- plied in four colours for ease of Identification. Each address should be wired using connectors of the same colour and adjacent addresses using connectors of different colours.

  1. Autodials connected to a direct exchange line. To store a telephone number on the translation field, tag 1 of the chosen address is connected to the digit bar corresponding to the first digit of the telephone number, tag 2 is connected to the digit bar corresponding to the second digit and so on. When the last digit has been connected the next free tag is connected to the STOP bar.
  2. Public Network calls from a PABX. When public network calls are required from a PABX extension, a public exchange access digit is required, normally 9. By dialling this number access is provided to the public network, and, on receipt of dial tone, the remainder of the number is dialled. By connecting the ACCESS tag of an address to the EXCH bar the Autodial is programmed to dial 9, apply a two-second Inter-digital pause (to allow for the receipt of public exchange dial tone) and then transmit the national number.
  3. ISD telephone numbers. When an international number is required the ISD (International Subscriber Dialling) code 010 is set up by connecting the appropriate ACCESS tag to the ISD bar, the remainder of the number being connected as in para a above. If the ISD number is required from a PABX extension, the permanent straps cause the digit 9 and a long interdigital pause to be transmitted before the 010.
  4. Local PABX numbers. The translation field is wired as for a direct exchange line and the ACCESS tag is left spare.
  5. Spare addresses. These should be left unconnected.

Labelling of Key Unit Buttons
The name should be written (or typed) on the centre portion of the label and the number may be written on the side section. The label is held captive by the transparent button top. To gain access to the label the transparent top should be gripped by its longer sides and gently pulled off the button.

Testing and Operation
Connect a test number to an address in the translator. Ensure that the power supply and the ON/OFF switch (bottom right of key-pad) on the Key Unit are both ON. The left-hand lamp on the Key Unit should now glow.

Check the telephone instrument can be used in the normal manner.
Operate the appropriate address button and check the following:-

  1. Ensure the address button locks down.
  2. The right hand lamp on the Key Unit glows (green).
  3. When pulsing has ceased the supervisory tones should be heard on the monitor amplifier loudspeaker. (To adjust the level see para g).
  4. When the handset of the telephone is lifted, the address button should release, the right hand lamp ceases to glow and the monitor amplifier should be disconnected. Conversation may now proceed.

    Replace the handset and check the cancel button as follows:-
  5. Re-operate the address button and ensure that, when the cancel button is operated, the Autodial releases.

    To check the time-out circuit proceed as follows:-
  6. Repeat (a), (b) and (c).
  7. Wait for approximately 60 seconds after the end of dialling without lifting the telephone handset. The call should then automatically release. When the checks have been made remove the test number and connect the addresses required by the subscriber.

It should be noted that when the autodial is connected to an extension plan and a call has been originated by the autodial, the lifting of an extension telephone handset will cause the autodial to release.

Monitor Amplifier Volume Control
It should be ensured during testing that the signals in the monitor amplifier loudspeaker are at a satisfactory level for the subscriber. If necessary the level may be adjusted by a variable resistor (RV7) situated in the translator on the lower printed circuit board below terminals 35 and 36. When the volume has been adjusted to a satisfactory level the translator terminal cover must be replaced.

Wiring details are shown in Diagram N 2310.

Diagram SA 9199 shows the circuitry of the Autodial and Diagram Notes SA 9199 explain the circuit operation.


The lamps may be changed (Lamps No. 41 B), buttons inspected, and wiring checked.

To inspect the key unit remove its four base screws, this gives access to the connection cord. For access to the lamps and keys the fascia panel is removed by undoing the two screws found in the centre of the Latch Mechanism support bracket .

When replacing the base do not forget the rubber sealing band. This is replaced by loosely fitting the base with its four screws then replacing the rubber sealing band before completely tightening the base screws.

The complete unit may be changed by unplugging from the Box Connection 6A.

Most of the Electronic components in the translator are enclosed and cannot therefore be maintained in the field.  However jumper connexions should be checked (these can be altered by customers) if wrong number faults are reported.   Access can also be gained to the 41 wire and 4 wire cables by removing the four corner screws of the metal surround.

This surround also gives access to four variable resistors.

Power unit maintenance is restricted to changing fuses.

If faults cannot be located and cleared in this limited way then the faulty unit must be changed. Spare equipment if not held locally, is held at the P.O factory (Enfield) as detailed in T1 E5 A0015.

Whilst waiting for parts ordinary exchange line facilities should be provided.

NOTE - The translator contains a mercury wetted reed relay and will not work unless mounted vertically.

Customers are permitted to make their own changes to stored numbers and they should be encouraged to do so. When a customer specifically asks the PO to change one or more numbers in the store, the request should be directed to the Sales Division where an Advice Note will be issued for the work to be completed by the Installation Group.

Requests for maintenance staff to make changes to the number store when they are at a customers' premises for other work should be met and the charge raised by way of the A864 procedure (See Booklet A44).

Write the number down and tick each digit as it is connected. Select the key to be used, the translator tags for keys 1-16 are the left hand side and for keys 17-32 the right hand side of the translator.

Connections can now be made using Connectors 1001A (use same colour for each separate address) between the tags associated with the key and the digit bars (centre of translator).

Tag 1 of the key is connected to the bar representing the first digit of the number, tag 2 to the second etc. When all the digits have been connected the next tag is connected to the stop bar.

See picture below. Button 1 shows a PABX extn or DEL Autodial, connected to Address 4198 i.e. PABX Extn 4198 or own Exchange 4198.

PABX Extensions
If the Callmaker is connected to a PABX extension and the call being set up is to be via the public exchange, the 'Access' tag is connected to the bar marked 'EXCH', this provides the digit which is dialled for the public exchange. Button 2 in the picture below shows an example of a PABX Extn connected to Address 9.2570.

International Calls
The 'Access' tag is connected to the 'ISD' bar. This provides the code '010' - or, in the case of PABX extensions, the public exchange code followed by '010'.  Button 3 in the picture below shows an International Address Paris 24680 i.e.

Other Information
The bulbs are Lamps No. 41B.

Extract from an article on Repertory diallers in the POEEJ, Vol ume62, page 188, October 1969.

Repertory Diallers

Repertory diallers enable an individually selected variety of national or international calls to be set up automatically by a simple operation, such as the pressing of a button. Three types are described which use three fundamentally different methods of information storage. All give a considerable time and effort saving over the conventional dial.

A repertory dialler is a device which can be programmed with a repertoire of telephone numbers, so that by a simple operation the user can cause a selected number to be automatically dialled.

About thirty-years ago the Post Office introduced the Autodials No. 1 and No. 2, which were mechanical repertory diallers, the digits of the telephone number being represented by teeth on a brass disc. To dial a number, pulsing contacts were positioned so that they were operated by the teeth when the disc rotated. For various reasons the production of autodials was discontinued.

In recent years there has been a revival of interest in repertory diallers and the Post Office has been studying the market requirements of three categories of dialler. For marketing purposes these three types are known as the Key Callmaker, Tape Callmaker and Card Callmaker. Engineering titles are Autodial 100 series, Autodial 200 series and Autodial 300 series, respectively. The Post Office has sponsored the development of the key and card callmakers and purchased a quantity of tape callmakers for market trials. The three autodials are described briefly below.

The Autodial No. l0lA is an executive-style instrument, giving access to any one of 32 telephone numbers at the press of a button. A simple amplifier and loudspeaker are provided to monitor the progress of a call, so that the handset of the associated telephone instrument need only be lifted for conversation when the call has matured. The dialler comprises a desk tablet, the Key Unit No. 1A, which measures 9 in x 7.5 in x 3.5 in high, and a wall-mounted unit, the Translator No. 1A, with an associated mains-driven power unit.

The Key Unit No. 1A houses the 32 address buttons, arranged in four columns of eight, and a further button for cancelling calls. The buttons have a face area of 1.25 in x 0.3 in and each is provided with a paper designation label protected by a transparent-plastic cap. Each button has a single sealed make contact which is operated by the movement of a permanent magnet. Once depressed, an address button is locked down by a solenoid to hold the contact made for as long as the autodial is controlling the call. Located in front of the address buttons, beside the cancel button, is a miniature loudspeaker for the monitor facility. On the other side of the cancel button are two warning lamps. One is lit when the autodial is operational, the other when a call is being dialled or held.

The Translator No. 1A, which should be mounted in a discrete but accessible position, contains the telephone-address translation field and all the electronic circuitry. The translation field (shown to the right) has 32 groups of 13 tags, one group associated with each address button. The first tag of each group is labelled ACCESS and the other tags are labelled 1-12.

Between the two columns of tag groups are 14 slotted bars representing digit values 1-0, EXCHANGE, ISD, STOP, and a spare bar which can be cross connected to any other bar to give extra connexion capacity. Wire jumpers, 44 in long, with crimped connectors, are used to connect the tags to the bars. The jumpers are supplied in four colours, red, white, blue and black, to assist identification if number changes are required.

Address Translation
To programme a telephone number, tag 1 of the chosen address group is jumpered to the digit bar corresponding to the first digit of the telephone number, tag 2 to the bar corresponding to the second digit, and similarly for the other digits. After the last digit has been connected, the next free tag is jumpered to the STOP bar, to provide an end-of-number signal.
Public-network calls from p.a.b.x. extensions are normally obtained by dialling 9 to gain access to the public exchange. On receipt of dial tone the remainder of the number is dialled. By jumpering the ACCESS tag of an address to the EXCHANGE bar, the autodial can be programmed to dial 9, pause for two seconds and then transmit the telephone number.
When an international number is required, the international access code 010 (or 9010 from a p.a.b.x. extension) is set up by jumpering the appropriate ACCESS tag to the ISD bar, the remainder of the number being connected as before.

Exchange-Line Connexion
The autodial is designed to be connected between the incoming line and the telephone installation, and is therefore provided with independent pulsing and line-hold circuits (see diagram below). Because the autodial is connected to a line rather than a telephone instrument, it is not suitable for connexion to certain installations, such as p.b.x. switchboards.

The pulsing-relay contact is a mercury-wetted reed with a standard spark quench. During dialling the telephone line is short-circuited behind the pulsing contact by the mask-relay contact. At the end of dialling this releases and allows the monitor amplifiers and loudspeaker to reproduce supervisory tones and called-subscriber answer. The monitor amplifier is provided with automatic gain control so that tones in the level range -30 dBm +6 dBm can be reproduced.

Outline Circuit Operation
As an example, assume address No. 4 has been programmed with the local director number 246 8071. To call this number the user presses button 4 which triggers the control circuit and selects the address. Immediately, the control circuit returns a potential to the key unit which energizes a solenoid and locks the button down. Further signals from the control circuit operate the mask relay which loops the line ready for pulsing, and connect the monitor amplifier behind the dialling loop.

After a two-second pause to allow for the seizure of the exchange equipment, the pulse generator is allowed to free run at l0p.p.s. As each pulse is sent to line the pulse counter is stepped on until coincidence occurs with the value programmed for the first digit; a signal is then forwarded from the coincidence circuit to the inter-digital pause (i.d.p.) generator to give an 800 ms pause and to clamp the pulse generator. In the example, the value of the first digit is 2. A further signal Steps Oil the address-code selector so that the second digit, 4 in the example, is presented to the coincidence circuit. At the end of the 800 ms pause the pulse generator again free runs at l0p.p.s. until the pulse counter has counted four pulses, when coincidence again occurs. The process is repeated until the address-code selector steps to the eighth digit. The eighth digit tag has been jumpered to the STOP bar. The pulse generator is therefore clamped and the mask relay is released, removing the short-circuit from the input to the monitor amplifier so that supervisory tones and the called subscriber’s answer can be heard. When the handset of the associated telephone instrument is lifted, the line current through the telephone circuit is detected, and the monitor amplifier is released from the line, leaving the call under the control of the telephone. If the telephone handset is not lifted within one minute after the end of dialling, the time-out circuit releases the call and restores the autodial to the standby state.

International Calls
When a call to an international number is initiated, the ISD-code selector is activated to cause the prefix-code 010 to be transmitted. The ISD-code selector has a two-stage binary counter which controls the prefix digit-sequence.

The values of the digits are determined by the coincidence circuit as for national-number digits. The use of a special ISD-code selector reduces the number of digit tags by three for each address, and associated components by 3 resistors and 1 diode per tag. Elements in the address-code selector which would be required to select digits 13, 14, and 15 are also not required.

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Last revised: February 10, 2022