plessey1.jpg (6468 bytes)PLESSEY

Private Automatic Branch Exchanges

Plessex Kl

plessxk1.jpg (26774 bytes)K1 is a fully solid state processor control led telephone switching system which has been designed to combine the flexibility of key-systems with a range of sophisticated PABX features far beyond those found in currently available equipment.

The system is intended for use in small high traffic business organisations and has a traffic capacity of 20 erlangs. It provides a maximum of 96 extensions, access to 30 exchange fines and other services of various types, including interface to conventional telephones.

Design features
The equipment cabinet is attractively styled and compatible with a modern office setting and occupies approximately 3 sq. ft.

Dimensions are:-
height 0.66m
width 0. 79m
depth 0.37m

weight 78kg

A solid state switching medium and electronic technology provide a totally silent system with enhanced reliability, flexibility and transmission characteristics.

Fast economic installation by the use of quick connect tag blocks situated inside the cabinet.

Rapid commissioning complete exchange assembled and factory tested before delivery.

Easy growth and minimum disturbance all equipment’s are plug in P.C. B. modules. Test routines faulty equipment can be readily identified by test procedures from any extension. Call queuing calls answered in order of arrival.

Standard Kl extension instruments are provided with a 12 button key pad and 4 LED indicators to show call status. A tone sounder is provided instead of a bell.

Facilities are: -

3 digit extension numbering 201-296.

Automatic access to exchange lines and other services.

Call hold all calls.

Enquiry all calls.

Transfer all calls.

3 way conference all calls.

Brokers enquiry all calls.

Incoming group calls

Exchange lines, can be arranged into 3 groups and automatically extended to extensions, or groups of extensions, without the intervention of the attendant.

Individual exchange lines can also be extended to dedicated extensions.

Night service common on dedicated extension answering is provided.

Programmable class of service (C.O. S.)
Programmable system options include the following

(i) Follow me permits extensions to divert I/ C calls to any other extension.

(ii) Call pick up any extension hearing the sounder of another instrument, can key a pick up code and answer the call at his own instrument.

(iii) Double row working whilst engaged on any type of call on the first row, the user can receive and originate other calls.

(iv) Group call control permits extensions to temporarily divert group calls to himself.

(v) Night service control allows extensions to determine when night service working applies to exchange line groups of which he is a member.

(vi) Programmable dedicated night service answer by combining the features of (i) and (v)

D.N.S. extensions can temporarily divert night service answer to any other extension.

(vii) Route restriction up to 4 digit analysis of 0/ G calls is provided.

(viii) Short code dialling a common library of 96 codes up to 16 digits in length.

(viiii) Paging access 2 digit access to a maximum of 3 zones.

Test routines enables a maintenance engineer to select any predetermined path through the system and provides a means of fully testing the extension instrument.

Manual recall enables extension on hold to attract attention of controlling extension.

Attendant's Console
When, provided the attendant has available the following facilities.

Switched loop operation provides the attendant with 5 connect CCTS.

Non-delay working enables the attendant to extend digit '0' assistance calls to the public exchange without the need to ring back.

Calling line identification digital display of the extension number, or exchange line identity to whom the attendant is speaking.

Keypad verification digital display of key pad button which is depressed.

Paging access.

Series call enables the attendant to extend the I/C caller to successive extensions.

Recall enables the attendant to be recalled if extended calls are not answered with 30 secs. or if an extension wishes to co-opt the attendant into an established call.

Intrusion into busy calls with warn tone.

Group call diversion group calls that are not answered within 30 secs. appear at the console but continue to call group members.

Group call control enables the attendant to temporarily divert 1/C group calls to the console.

Digital clock.

Exchange line reserve enables the attendant to reserve exchange lines for her own O/G traffic without inhibiting I/C calls.

Emergency barge in when an emergency situation arises the attendant can barge in to a busy exchange line if no others are free.

Congestion and system alarm indicators.

Options Requiring Additional Hardware:

Direct dialling in exchange lines (DDI).

Tie lines.

Tandem switching.

Paging access CCTS.

Dictation access CCTS.

Mains fail
Under mains fail conditions up to 8 exchange lines can be diverted to conventional telephone fitted with earth calling buttons.

Interface to off-premise extensions (OPX) provides access to conventional telephones with line length up to 1000 ohms.

MF receivers required when OPXs are fitted with touch tone key pad.

Group sets similar appearance to standard Kl instruments with 4 additional LEDs and buttons. This enables the G. S. instrument to be programmed to answer any 4 extension calls, or group calls, in addition to his own calls.

Callmaster similar function to G.S. instruments but with 100 buttons and LEDS.

Taken from the Plessey Publication No. 7665, 5/76

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Last revised: October 10, 2019