NMX920 OEM Integrators Guide
Page 11 of 21
q
POWER-OFF MODE
– this mode is selected when the NMX920 is not required to
communicate with the MOBITEX network to send and/or receive messages, or the
NMX920 is to have its power disconnected. Power consumption is reduced to a
minimum in this mode by switching off most internal devices, including the
microprocessor and MASC interface. The NMX920 is waiting to sense a “power on
request” via the correct assertion of the
DTR
pin (see section
….
above). This will
cause the NMX920 to enter its last known operational state (ie. either
EXPRESS
or
BATTERY
SAVE
MODE
, whichever mode was active when
POWER-OFF MODE
was entered.)
q
EXPRESS MODE
– in this mode the NMX920 the radio is always powered. Radio
conditions permitting, the NMX920 will contact and register with the MOBITEX
network and is able to send and/or receive messages. The NMX920 will enter
BATTERY SAVE MODE
when the MASC FY command or MODE MPAK is issued.
Alternatively, the NMX will return to
POWER-OFF MODE
by issuing the MASC FO
command.
q
BATTERY SAVE MODE
- this mode is functionally similar to
EXPRESS MODE
except that the Radio Module runs on about 10% duty cycle to reduce the average
power consumption.
6.1. Application of power
Electrical power must be applied to the NMX920 via the
PWR
pins of the
External
Interface
. The NMX920 will power-up, run internal diagnostics and then enter
POWER-OFF MODE
. The designer should allow at least 2 seconds between the
application of power and the first attempt to communicate with the NMX920 to
change out of
POWER-OFF MODE
.
6.2. Network Contact
Once power has been applied according to Section 6.1 the NMX can be brought
into Network Contact (ie. either
EXPRESS
or
BATTERY MODE
) by toggling
DTR
to it’s active state.
The NMX920 will issue a MASC B frame to initialise the MASC interface, and begin
MOBITEX network roaming and contact. From this point on the MASC interface is
active and controls the behaviour of the NMX920.
NOTE: Application of DTR for duration less than 1000ms will initiate internal
diagnostics and return to POWER-OFF MODE.
6.3. Mode Change
The NMX920 can toggle between
EXPRESS MODE
and
BATTERY SAVE MODE
while in network contact using one of the following mechanisms:
1. MASC FY command is issued.
2. MODE MPAK issued at MASC interface.
The NMX920 will contact the network to toggle modes, this operation involves
packet transmission and can take up to two seconds.
