GENERAL NOTES
SUMMARY OF XSF FLAGS
(Communications Operation of XSF flags is required)
XSF1 - Inhibits calls for SG1 from queue detectors 1, and 2.
XSF2 - Place a permanent demand for BØ.
GENERAL OPERATION
1.                  The introduction of SG2 conditional on the termination of SG1.
2.                  BØ is provided to meet the SCATS requirement of a minimum of two phases.
3.                  SG1and SG2 use the yellow time of the phase in which they close down and the red times specified in the Special Movement Timesetting Nos. 1and 2 respectively.
SIGNAL GROUP OPERATION
Signal Group 1
1.                  For SG1 minimum green time refer to Special Purpose Timesetting No. 9.
2.                  For SG1 maximum extension green time refer to Special Purpose Timesetting No. 11.
Signal Group 2
1.                  For SG2 minimum green time refer to Special Purpose Timesetting No. 10.
2.                  For SG2 maximum extension green time refer to Special Purpose Timesetting No. 12.
3.                  Detectors 3 and 4 extend AØ.
DETECTOR OPERATION
Queue Detectors 1 and 2
1.                  Queue detectors 1 and/ or 2 place non-locking calls for BØ when their presence timers have expired.  XSF1 inhibits calls for SG1 from queue detectors 1 and 2.
2.                  Queue detectors 1and 2 extend BØ.
3.                  Queue detectors 1and 2 do not alarm in the ‘OFF’ state.
4.                  If detector 1 is ‘ON’ continuously, the queue function will not be recalled by detector 1 until detector 1 changes state from ‘ON’ to ‘OFF’.
5.                  If detector 2 is ‘ON’ continuously, the queue function will not be recalled by detector 2 until detector 2 changes state from ‘ON’ to ‘OFF’.
6.                  The failure of detectors 1 and 2 in the ‘ON’ state will flag a ‘DA’ alarm for monitoring purposes.
Queue Detectors 3 and 4 
1.                  Queue detectors 3 and 4 extend AØ.
2.                  Queue detectors 3 and 4 do not alarm in the ‘OFF’ state.
3.                  If detector 3 is ‘ON’ continuously, the queue function will not be recalled by detector 3 until detector 3 changes state from ‘ON’ to ‘OFF’.
4.                  If detector 4 is ‘ON’ continuously, the queue function will not be recalled by detector 4 until detector 4 changes state from ‘ON’ to ‘OFF’.
5.                  The failure of detectors 3 and 4 in the ‘ON’ state will flag a ‘DA’ alarm for monitoring purposes.