Toshiba HHGP1 - Manual (Page 34)

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1. Time Signal Transmission Format
The time signal format is shown below, consisting of 4,800bps serial data indicating the time,
and 1PPS timing signal indicating the instant of time corresponding to the serial data.
Serial data
4800bps
1PPS timing signal
Signal for next second
Signal code format: ASCII codes based on NMEA-0183 data
Output data: GPtps data (time and 1PPS flag)
GPtst data (self-test result)
2. Date Rollover
The GPS week number sent from the satellite returns to 0 (i.e., rollover) every 19.6 years;
therefore, the GPS receiver unit cannot output the date data correctly. This is the rollover
problem. To solve this problem, the GPS receiver unit provides a DIP switch.
- When the DIP switch 4 is set to OFF and the power is ON, the GPS receiver unit starts
outputting the date and time from any date between April in 2001 and September in
2020.
- When the DIP switch 4 is set to ON and the power is ON, the GPS receiver unit starts
outputting the date and time from any date between October in 2019 and March in 2039.
The default setting of the DIP switch 4 is OFF. After 2020, the DIP switch 4 should be set ON so
that the GPS unit outputs the date data correctly.
Note 1: The date and time data from the GPS receiver unit are used for the recording data of
GRL100 relay and do not influence the function of GRL100 relay. The 1 PPS signal is
output independently of the switch 4 setting.
Note 2: For one year from October, 2019 to September, 2020, any setting of the DIP switch 4 is
allowed. So, in this term, the changing of the DIP switch 4 is recommended.
3 High-reliability Mode and TRAIM Function
TRAIM (Time Receiver Autonomous Integrity Monitoring) is a function which allows the unit to
detect an error in the signal from a satellite. For operation of this function, it is necessary to
receive one additional signal to the minimum number normally required for output of the 1PPS