|P.O. ENGINEERING DEPT.
Issue 1, Feb 1960
SUBSCRIBERS' ORDER-TABLE EQUIPMENT
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.
The terms used in this Instruction and the relative diagrams, etc., are defined below:-
(a) Unit - One Key and Lamp Unit, SA 4062 (i.e. one order-table clerk's position).
(b) Table - A number of units over which a group of lines is multipled.
(c) Suite - In large installations several tables may be provided, which are
collectively called a suite.
(a) 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.
(b) 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
(c) '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.
(d) 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:-
(a) 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.
(b) 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.
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
Two types of desk unit are available:-
(a) For up to 80 lines, using Switchboard, Phonogram, No. 1A.
(b) For up to 120 lines, using Switchboard, Phonogram, No. 3.
Each unit is fitted with a
'calling' and 'engaged' lamp per line. A jack field with facilities for testing, patching
and listening-in is also provided.
The following diagrams apply to Order-Table Equipment No. 2:-
||Power supply to relay-sets and turret positions
||Line circuit. Exchange lines and P.B.X. extensions
||Line circuit. Private circuits and extensions from desk unit to telephone terminations
||Testing panel and patching board with observation facilities
||Operator's cord circuit with super- vision on private circuits
||Cabling to relay-sets
||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:-
(a) Up - RECEIVE CALL, (The key is normally left in this position)
(b) Normal - CALL
(c) 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.-
(a) 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.
(b) 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.
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:-
||Line equipment. Exchange lines and P.B.X. extensions
||Line equipment. Private circuits and telephones
||Shelf jack wiring for Relaysets
||Key and lamp unit
||Typical power supply and cabling
||Common equipment relay-set
||Order table apparatus rack - Assembly of equipment