SK Radon Hut - Center Hut communication: Blackbox and Femco Phone

HGB, updated May 28, 2002.

Communication between the SuperK control room and the radon hut is established over a 2-km long 6-conductor cable (3 twisted pairs) through the Atotsu tunnel. 4 of the conductors (2 pairs) are used for the serial port link between the PLC controller in the radon hut and sukslc (slow control computer) in the SK central hut. The other 2 conductors (1 pair) are used for a voice connection with mine phones (Femco phones).

Radon Hut serial port link via BlackBox modules:

In order to transmit 9600 baud serial data over the 2-km distance between the radon hut and Super-K center hut / control room, a "Multi-point Mini Driver", made by BlackBox Inc., was chosen. These drivers are self-powered through the serial port control signals and convert the single-ended RS232 XMT signals to differential digital signals (like RS485) and back to single-ended RS232 RCV signals on the opposite end of the cable.

Communication Cable and Blackbox configuration table: