Motorola VRS750, Service Manual

Page: 44 / 104

32
If unit B activates its VRS during portable transmissions, unit B does
NOT transmit Single Tone or enable in delay state zero. Unit B must
wait until it cannot detect the portable signal before transmitting
Singletone and taking over as the priority unit as described above.
Three-Unit Operation
Should another VRS-equipped vehicle (unit C) come into the area, the
same sequence of events occurs as previously described in the “Two-
Unit Operation” section on page 31. Unit C’s arrival has no effect on
unit A’s or B’s radio operation until unit C’s VRS is enabled.
Unless there are portable transmissions occurring when unit C arrives,
unit C’s repeater transmits a Single Tone burst when its VRS option is
turned on. Unit C’s repeater priority counter initializes in delay state
zero, making unit C the priority unit. Unit A’s repeater/portable
receives unit C’s transmission which sets unit A’s repeater to delay state
two. Unit B’s repeater/portable receives unit C’s transmission which
sets unit B’s repeater to delay state one. Transmissions from portable
units in the area now repeat through unit C. All lower-priority units
will receive incoming portable transmissions, but will not key up their
mobiles because they are in a delay state. See Figure 21.
Figure 20. Two-Unit VRS Transmissions
UNIT A
“DELAY STATE ONE”
UNIT B
“DELAY STATE ZERO”
PRIORITY UNIT
MAEPF-26081-O
TRANSMITS TO
BASE STATION AND
MOBILE RADIOS
IN AREA
TRANSMITS TO
ALL REPEATERS AND
PORTABLE RADIOS
IN THE AREA