noosh wrote: > Martin Burnicki wrote: >> Neither the GPS nor the ADAM are NTP servers, so why should a client find >> it? > if i do the following > GPS-------------------------------> PC(NTP) > Serial Port > > the time is synchronized by GPS.
Right. However the PC is your NTP server and the GPS device is just a reference clock which is read by the GPS program running on the PC. >> What might be possible is to configure the local NTP daemon to read the >> "serial" ref clock via the converter's emulated port. > > What do u mean by that? how can i do that? can you give more detail of > your idea? In the figure above the GPS devices provides a serial port which is connected to one of the PC's serial ports. The NTP program on the PC opens that serial port and uses a special driver (e.g. the parse driver or the NMEA driver) to read the time from the GPS clock, depending of the string format send by the clock. >From your initial post: > this is my first time that i have to work with ADAM 4577. it is 1 port > universial serial gateway.now it is like this > > GPS ----------------->ADAM 4577 --------------------------------->PC1 > serial Port LAN > > unfortunatelly PC cann't find ADAM as its NTP Server. has anyone work > with this ADAM 4577? So ADAM is a serial-to-LAN converter which reads the serial output of the GPS receiver and puts those bytes into network packets which arrive at the LAN port of your PC instead of a serial port. I assume the format of those packets is proprietary since it must not only transport the raw byte stream from the GPS device but also the levels of the GPS devices serial control lines. The NTP program can only receive NTP packlets from another NTP server, not those proprietary ADAM packets. On the other hand, if you configure the NTP daemon on your PC to use the GPS device as a reference clock (as you would do without the ADAM) then ntpd tries to open the configureed serial port, set the baud rate etc. correctly, and receive the string from the GPS device. So if you want ntpd to read the serial time string from the GPS device then you have to install a driver on the PC which receives the proprietary network packets sent by ADAM, and appears like a serial device to the NTP daemon. Those drivers are normally shipped with the device, at least for Windows where they emulate a COM port e.g. COM20. You should see if the ADAM device comes with a Linux driver at all. And, please remember that network redirection of serial data introduces additional jitter, so the results may not be too good. Martin -- Martin Burnicki Meinberg Funkuhren Bad Pyrmont Germany _______________________________________________ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
