Automatic SwitchboardsPAX. 2000 - Open Rack Type
For very large establishments where the ultimate requirements will considerably exceed the number of lines that can be accommodated on our smaller PAX. switchboards, PAX. 2000 is used, as it provides for practically unlimited extension.
The apparatus is of the same design as that used in British Post Office public exchanges and is similarly protected from dust by means of. covers over the various units or, when specially required, by totally enclosing the racks.
Owing to the wide capacity limits of PAX. 2000, it cannot be standardized to the same extent as those described on the preceding pages, therefore the requirements of each are assessed and met in the most economical manner. A view of a typical 150-line equipment is illustrated above, the combined main and intermediate distribution frame being on the left and the charging panel in the foreground. It will be appreciated, however, that rack equipment arrangements vary considerably in exchanges of differing size.
As its name implies, PAX. 2000 utilizes British Post Office type "2000" selectors. Uniselectors of the B.P.O. type are also employed either as line switches or line finders according to requirements.
The illustration on the left shows one of the switching racks in the 150-line exchange shown on the previous page.
Long term economy in time and cost is effected if attention is given initially to the ultimate requirements, by the provision of banks and wiring in excess of the immediate needs, so that the equipment can be extended or rearranged to suit traffic fluctuations-a simple matter by virtue of the jack-in feature of the selectors and relay sets.
Balanced tones and pulses of the periodicities standardized for public exchange working are provided, together with suitable supervisory, fault alarm and testing equipment, but special facilities in this connection can be incorporated when required. Typical Rack Equipment.
Operating features applicable to PAX switchboards of the smaller types can be provided if desired, these include tie lines, preference, round call or person finder, conference, loudspeaker and party line working.
Further particulars of private automatic exchange equipments will be
furnished on request. The Company's organization is at your service to
assist in solving telecommunication problems.
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