Service manual

EXTERNAL SERIAL CONTROL PROTOCOL
B-9
September 1999
Part No. 001-9800-200
Figure B-2 Power-Down Request Accepted
Figure B-3 Broadcast Power-Down
Figure B-4 Power-Down Request Denied
Figure B-5 Addressed Power-Off
Subscriber Unit External Device
EVENT_POWER_OFF_REQUEST
[ POWER_OFF_REASON ]
ACK
[ DA = 0x?? ]
[ DA = 0x01 ]
The External Device shall
perform all power-down
activity needed and display
‘PWR OFF’ until the power-
down is granted.
If all registered External
Devices have been placed in
power down mode, then the
Subscriber Unit shall grant
the power-down request.
All External Devices shall
now proceed to power
themselves down.
The Subscriber Unit shall wait
until the
EVENT_POWER_OFF has
been fully sent, and then
proceed through it’s normal
power-down procedures.
[ SA = 0x?? ]
EVENT_POWER_OFF
[ DA = 0xFF ]
Subscriber Unit External Device
EVENT_POWER_OFF
[ DA = 0xFF]
If the Subscriber Unit
determines a power down is
needed or desired.
The Subscriber Unit shall
proceed to power down
normally.
All External Devices shall
now proceed to power
themselves down.
Subscriber Unit External Device
EVENT_POWER_OFF_REQUEST
[ POWER_OFF_REASON ]
N
A
K
[ DA = 0x?? ]
[ SA = 0x??]
The External Device shall
perform all power-down
activity needed and display
‘PWR OFF’ until the power-
down is granted.
If all External Devices have
N
OT been turned off or some
other condition precludes
power-down, then the
Subscriber Unit shall deny
the power-down request for
all External Devices.
The External Device shall wait at least one
second before retrying the power down.
If the NAK retry is not enabled, the user
must re-request the external device to
power down before sending again.
[ Error = Denied ]
Subscriber Unit External Device
EVENT_POWER_OFF
[ DA = 0x?? ]
If the Subscriber Unit senses
a reason to power down a
specific External Device.
The External Device shall no
longer access the data bus. It
shall indicate to the user that it
has be de-activated. To attempt
to access the data bus, it must be
power cycled and perform a
normal power up access attempt.
ACK