### JJY Receivers

Last update: 3-May-2011 00:20 UTC

#### Synopsis

Address: 127.127.40.u
Reference ID: `JJY`
Driver ID: `JJY`
Serial Port: `/dev/jjyu`; See corresponding receiver

#### Description

This driver supports the following JJY receivers sold in Japan.

- Tristate Ltd. JJY01, JJY02 http://www.tristate.ne.jp/ (Japanese only)

  NTP configuration ( ntp.conf )

    server 127.127.40.X mode 1

    fudge 127.127.40.X flag1 0|1

      Flag1 has no effect for time synchronization. When a flag1 is set to 1, status commands are issued before DATE and STIM commands, and write a response text into a clockstats file.

      0 (Default) | DCST and STUS commands are not issued
      1 | DCST and STUS commands are issued

  Interface

    RS-232C, 9600 baud, 8-bits, no parity, 1 stop bit

  Time code format

    Command | --> | Reply
    `date{CR}{LF}` | --> | `YYYY/MM/DD WWW{CR}{LF}`
    `stim{CR}{LF}` | --> | `HH:MM:SS{CR}{LF}`

- C-DEX Co.,Ltd. JST2000 http://www.c-dex.co.jp/ (Japanese only)

  NTP configuration ( ntp.conf )

    server 127.127.40.X mode 2

  Interface

    RS-232C, 9600 baud, 8-bits, no parity, 1 stop bit

  Time code format

    Command | --> | Reply
    `{ENQ}1J{ETX}` | --> | `{STX}JYYMMDD HHMMSSS{ETX}`

- Echo Keisokuki Co.,Ltd. LT-2000 http://www.clock.co.jp/ (Japanese only)

  NTP configuration ( ntp.conf )

    server 127.127.40.X mode 3

  Interface

    RS-232C, 9600 baud, 8-bits, no parity, 1 stop bit

  Time code format

    Command | --> | Reply
    `C` | --> | ( Mode 2 : Continuous )
    ( Every second before 0.5 second ) |  | `YYMMDDWHHMMSS{ST1}{ST2}{ST3}{ST4}{CR}`
    `#` | --> | ( Mode 1 : Request&Send )

- CITIZEN T.I.C. CO.,LTD. JJY-200 http://www.tic-citizen.co.jp/ (Japanese only)

  NTP configuration ( ntp.conf )

    server 127.127.40.X mode 4

  Interface

    RS-232C, 4800 baud, 8-bits, no parity, 1 stop bit

  Time code format

    Command | --> | Reply
    ( Every second ) |  | `'XX YY/MM/DD W HH:MM:SS{CR}`

- Tristate Ltd. TS-GPSclock-01 http://www.tristate.ne.jp/ (Japanese only)

  This driver supports the Tristate TS-GPSclock-01 in command/response mode, though it is a GPS clock, not JJY radio clock. Using the menus and the onboard switches, the TS-GPSclock-01 should be set to command/response mode and JST time zone.
  Besides this driver ( Type 40 ), the generic NMEA GPS driver ( Type 20 ) supports the TS-GPSclock-01 in NMEA mode.

  NTP configuration ( ntp.conf )

    server 127.127.40.X mode 5

    fudge 127.127.40.X flag1 0|1

      Flag1 has no effect for time synchronization. When a flag1 is set to 1, status command is issued before DATE and TIME commands, and write a response text into a clockstats file.

      0 (Default) | STUS command is not issued
      1 | STUS command is issued

  Interface

    USB ( /dev/ttyACM0 )

  Time code format

    Command | --> | Reply
    `date{CR}{LF}` | --> | `YYYY/MM/DD{CR}{LF}`
    `time{CR}{LF}` | --> | `HH:MM:SS{CR}{LF}`

JJY is the radio station which transmites the JST (Japan Standard Time) in long wave radio. The station JJY is operated by the National Institute of Information and Communications Technology. An operating announcement and some information are avaiable from http://www.nict.go.jp/ (English and Japanese) and http://jjy.nict.go.jp/ (English and Japanese)

The user is expected to provide a symbolic link to an available serial port device. This is typically performed by a command such as;

`ln -s /dev/ttyS0 /dev/jjy0`

Using RS232C to USB converter cable, the clock can be connected to an USB port instead of a serial port. In this case, typical symbolic link command is as follows;

`ln -s /dev/ttyUSB0 /dev/jjy0`

Windows NT does not support symbolic links to device files. COMX: is the unit used by the driver, based on the refclock unit number, where unit 1 corresponds to COM1: and unit 3 corresponds to COM3:

#### Monitor Data

The driver writes each timecode as received to the `clockstats` file.

#### Fudge Factors

`time1 time`
  Specifies the time offset calibration factor, in seconds and fraction, with default 0.0.
`time2 time`
  Not used by this driver.
`stratum number`
  Specifies the driver stratum, in decimal from 0 to 15, with default 0.
`refid string`
  Specifies the driver reference identifier, an ASCII string from one to four characters, with default `JJY`.
`flag1 0 | 1`
  See corresponding receiver.
`flag2 0 | 1`
  Not used by this driver.
`flag3 0 | 1`
  Not used by this driver.
`flag4 0 | 1`
  Not used by this driver.