No. 2 and No. 3

A 1401
Issue 1, Feb 1960

General Description

In certain types of business organisations such as departmental stores, ticket agencies, etc., a large proportion of the incoming traffic is of a well defined and specialised nature and can therefore be directed to a group of employees who will deal exclusively with such traffic.  Order-table equipment is designed to enable such businesses to handle this specialised traffic in the most advantageous and expeditious manner.  Each unit has a capacity of 10 lines (exchange, extension or private wire) and each key has two associated lamps, coloured red and green.  A Telephone No. 164 or Receiver, Headgear  No. 9A and Transmitter No. 23 are required at each unit.

The terms used in this Instruction and the relative diagrams, etc., are defined below:-

  1. Unit - One Key and Lamp Unit, SA 4062 (i.e. one order-table clerk's position).

  2. Table - A number of units over which a group of lines is multipled.

  3. Suite - In large installations several tables may be provided, which are collectively called a suite.


  1. Exchange lines, extensions from a P.B.X. switchboard, or, private circuits can be terminated on order-table equipment, and can be used for both incoming and outgoing calls.

  2. Lamp calling signals and an audible alarm are provided, and the lines are ancillaried over all units of one table, so that a call can be answered by any clerk on that table.

  3. 'Engaged' lamps are also provided on all lines, and glow as soon as a line is taken into use for either an incoming or outgoing call.

  4. Order-table equipment does not cater for the interconnection of circuits. One of the main advantages of order-table equipment is that it facilitates a rapid speed of answering if the installation is correctly planned. It is therefore recommended that the number of units provided should, in general, approach the number of lines on which calls can be answered.

Order-table equipment is not intended to be used as a concentrator keyboard when lamp signalling is requested.  The auxiliary equipment is unnecessarily expensive when used for this purpose and provides facilities which are not required when only a single-position concentrator is called for.  Requests for a lamp-signalling concentrator should be dealt with as for a non-standard facility.

Types of equipment
Two types of order-table equipment are available:-

  1. Order-Table Equipment No. 2, which is intended for very large installations; generally, where access to more than 30 lines per clerk is required.

    Desk units are provided and the installation is described later.

  2. Order-Table Equipment No. 3, which will meet the needs of the majority of small or intermediate installations, e.g. where each clerk may have access to up to 30 lines.

Description of Order-Table Equipment No. 2
This is intended for installations where more than 30 lines are to be terminated, but this condition is rarely encountered.

Clerks' positions
The circuits, which may be exchange lines, P.B.X. extensions or private circuits, are multipled on jacks on desk units in front of the clerks.  Each unit has accommodation for two clerks who are each provided with two cord circuits, enabling one call to be held while another is made for an inquiry. The equipment does not cater for the interconnection of circuits.

Two types of desk unit are available:-

  1. For up to 80 lines, using Switchboard, Phonogram, No. 1A.

  2. For up to 120 lines, using Switchboard, Phonogram, No. 3.

Each unit is fitted with a 'calling' and 'engaged' lamp per line which are coloured red and green.  A jack field with facilities for testing, patching and listening-in is also provided.

The following diagrams apply to Order-Table Equipment No. 2:-

SA 4051  

Typical layout

SA 4052  

Power supply to relay-sets and turret positions

SA 4054  

Line circuit. Exchange lines and P.B.X. extensions

SA 4055  

Line circuit. Private circuits and extensions from desk unit to telephone terminations

SA 4056  

Testing panel and patching board with observation facilities

SA 4057  

Operator's cord circuit with supervision on private circuits

SA 4058  

Cabling to relay-sets

SA 4066  

Common equipment relay-set.

Description of Order-Table Equipment No. 3
The majority of requests for order-table equipment can be met by the provision of this type, which consists basically of Key and Lamp Units, SA 4062.  These are 10-Line units and are normally provided on the basis of one per order clerk.

The lines, which may be exchange lines, P.B.X. extensions or private circuits, are multipled round the key and lamp units so that each clerk has access to every line terminating on that particular table.

Key and Lamp Unit, SA 4062
This unit consists of a wooden case with a sloping front, housing ten line keys, each with an associated red calling lamp and a green engaged lamp, the operator's circuit and a Jack No. 20 for the operator' s instrument.

The line keys are locking three-position lever keys, the positions being:-

  1. Up - RECEIVE CALL, (The key is normally left in this position)

  2. Normal - CALL

  3. Down - SPEAK

The operator's instrument may be either a telephone handset or headgear receiver. and breastplate transmitter as desired. Provision is made for the addition of a dial. The physical design of the unit is shown on Drawing 63441 and the circuit on Diagram SA 4062.


Since the key and lamp units do not contain signalling equipment, separate relay-sets are necessary. Two types are available:-

  1. Relay-set SA 4054 provides for generator incoming and loop-call outgoing signalling and is suitable for terminating exchange lines and extensions from P.B.X. switchboards. Each relay-set has a capacity for five circuits.

  2. Relay-set SA 4055 provides for loop-call incoming and generator outgoing signalling; thus it can be used for working to single telephones or on private circuits routed over physical pairs. Each relay-set has a capacity for two circuits.

Since no ringing keys are fitted on the Key and Lamp Unit, SA 4062, operation of the key to the SPEAK position causes the Relay-set SA 4055 to extend interrupted ringing to line, ring-trip occurring during a silent period. interruption of the ringing is provided by a common relay-set, designated Relay-set SA 4066, made up locally, Diagram SA 4066 giving the circuit and apparatus schedule.  It consists primarily of a start relay and two interacting slugged relays which provide the interrupted 'X' pulse.  By the addition of two relays to provide interrupted 'Y' pulses, flashing calling signals can be provided on the key and lamp units, should the subscriber request it.  It should be noted that 'flashing-call' is not a normal facility.

Auxiliary equipment
Relay-sets are of the jacked-in type and in consequence Shelves, Channel Type D 9549.... must be provided.  These can be mounted on wallboards for small installations, but for larger installations siting of an apparatus rack must be considered when accommodation is being arranged.  The 'calling' and 'engaged' lamps are Lamps No. 6v, fed from a 6v a.c. supply derived from the mains.  The transformer used for this purpose should be mounted on the wallboard or apparatus rack, as appropriate.  If required, ringing supply is provided by a Power Unit SA 1013 similarly mounted or from an exchange ringing lead, whichever is the more economical (POWER General, S 0901 refers).

The following diagrams apply to Order-Table Equipment No. 3:-

SA 4054 Line equipment. Exchange lines and P.B.X. extensions
SA 4055   Line equipment. Private circuits and telephones
SA 4058   Shelf jack wiring for Relay-sets
SA 4061   Typical layout
SA 4062   Key and lamp unit
SA 4065   Typical power supply and cabling
SA 4066   Common equipment relay-set
Drawing 90826   Order table apparatus rack - Assembly of equipment
Drawing 90827   Rack details.

Click here for an article on Order-Table equipment.

Click here for more information on the Key and Lamp Unit SA4062.

Click here for an early type of Order-Table Working.

Click here for pictures of the Order-Table Equipment No. 2.

Click here for pictures of the Order-Table Equipment No. 3.

Superseded by the Key and Lamp Unit No's 2A and 10A.



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