PXML No. 49
APPROVAL No. S/2374/3/D/450230
EK612 is a stored program control (SPC) SCRApp employing micro-processor control techniques. The system consists of a key service unit (KSU) incorporating a 240V power supply and a single type of telephone instrument.
All power requirements are fed via the 240V supply. Visual indication of call progress may be given by lamps associated with keys on each telephone instrument. Interconnection between the KSU and the extension telephone instruments is via an MDF. A single 50-wire cable connects the unit to the MDF and four-wire cables are then fed to each instrument via a plug and socket. Power fail facilities are provided by any compatible approved extension telephone via an appropriate socket (e.g. Line Jack Unit 2/1A). The MAXIMUM loop resistance of this systems extension wiring (speech pair only) is 50 Ohms.
NOTE. This system MUST ONLY be connected in a multi-exchange line configuration.
MAXIMUM CAPACITIES OF THE CONTROL UNIT MODULES
NOTE: This unit has no serviceable parts and no maintenance should be undertaken on site.
Maximum instrument line length is 50 ohms.
Type B classification power feeding (speech path power is derived from systems own power supply).
Earthing for system is via mains plug.
Introduced in 1983.
See also BT S6022/Marquis 1
Last revised: November 27, 2010