Motorola M12 Oncore User Manual page 10

9. Features
9.1 Differential operation
Motorola binary corrections on TTL RXD1 (pin 2) at 9600 baud
RTCM SC-104 Type 1 and Type 9 corrections on TTL RXD2 (pin 8) at 2400 or 9600 baud
9.2 NMEA 0183 output
NMEA 0183
Messages supported
9.3 User definable datum
One user definable datum may be defined using the @@Ap command. The default datum is
WGS-84.
9.4 Antenna sense circuit
The M12 Oncore receiver is capable of detecting the presence of an antenna. The receiver
utilizes an antenna sense circuit, which can detect under current (open) and over current
(shorted or exceeding maximum limit) conditions. The status of the antenna circuit is
reported in the Position/Status/Data Message (@@Ha), the Short Position Message (@@Hb)
and the Self-Test Message (@@Ia).
The antenna sense circuit is useful for verifying that the antenna is properly connected to the
receiver and is drawing the proper amount of current. The antenna sense status should be
checked after installation and monitored regularly.
Undercurrent indication < 8 mA
Overcurrent indication
9.5 Real time clock
The real-time clock (RTC) is a standard feature on the M12 Oncore. It is used to minimize
the time to first fix (TTFF). The date and time will be retained in the RTC if battery backup
power is applied when main power is off.
The user has two options regarding time initialization:
1) Set the date and time BEFORE the receiver acquires any satellites
2) Let the receiver automatically set the date and time AFTER acquiring the first satellite
Note: The date and time cannot be manually set while the receiver is tracking satellites.
Without battery backup, the receiver will start-up with a default time of 12:00:00. To obtain a
faster time to first fix, the time, date and GMT offset should be initialized if both the main
power and battery backup power have been disconnected.
Motorola GPS Products
M12 Oncore User' s Guide Supplement
Revision 1.0 01/25/00
Output on TTL TX1 at 4800 baud
GGA, GLL, GSA, GSV, RMC, VTG, ZDA
> 80 mA
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