ashtech HDS800, Reference Manual

Page: 53 / 678

37
Receiver Description
Event Marker Input
This input is used to time-tag external events. When an
external event is detected on this input, the corresponding
GPS time for this event is output as a $PASHR,TTT message
on port B. The time tag provided in the message represents
the exact GPS time of the event to within 1 μsecond.
Obviously, a single message is output for each new event.
Using the Event Marker input is a standard feature of the
receiver (no firmware option needed).
The event marker input is located on port B, pin 7.
You can choose whether it will be the rising or falling edge of
the event marker signal that will trigger the time tagging of
the event. This choice can be done using the $PASHS,PHE
command.
The signal specifications of the marker event input are the
following:
• Signal level: ± 10 V
• Permitted transient time on active edge: < 20 ns
Physical and Virtual Ports
Port ID Port Definition
A External serial port (RS232/RS422)
B External serial port (RS232)
C Bluetooth SPP
D Internal UHF radio
E Internal GSM/GPRS modem
F External serial port (RS232)
I External Ethernet (server)
I1-I9 Data streaming port on IP
M Internal memory
P, Q External Ethernet (client)
R Automatic recording session
U External USB memory