I am in the process of migrating my Trimble gps based NTP server from Windows to Linux.
For testing purposes, I am using an NMEA gps box, the BG7TBL unit with a u-blox NEO 7m. When I run the pps-tools ppscheck /dev/ttyS0, I see CTS asserting, which is the RS-232 line this gps unit ties to PPS (see attached png). However, when I run ppstest /dev/pps0 I receive time_pps_fetch() error -1 (Connection timed out). As such when I check chronyc sources, the PPS is registering as a source, but w/o data, i.e. Reach of 0 and LastRx of '-'.
How can I check that the linux PPS configuration to ensure it is not expecting DCD assertion or that pps0 is configured as a ldisc source?
Russ
PPSCheck.png