• 日本語
  • Print this page

The Telephone JJY service was terminated on March 31, 2024. The information on this page is kept for reference and historical purposes.

Supported commands

The commands listed below can also be seen in the terminal with the HELP or ? command. Send CR by pressing the enter key after the command string. The response will also be followed by CR.

Commands can be abbreviated to the first two or three characters, such that TIME can be sent as TI or TIM. Note that some commands are ambiguous when abbreviated to two characters, such that LO will be treated as LOOP, and executing the LOCAL command requires LOC to be sent. Commands and responses (except for INFO) are ASCII encoded, and commands work in either upper or lower case.

In the response format, hh, mm and ss are the hours, minutes and seconds respectively. DD and MM are the day and month. YYYY is the four-digit year, while YY is the last two digits of the year. 🛆 shows a space. Date and time are returned as Japan Standard Time unless noted otherwise.

Command Function
TIME Sends Japan Standard Time for 3 seconds, returns
hhmmss
JST Continuous transmission of Japan Standard Time, returns
hh: mm: ss continuously until CR is sent.
UTC Continuous transmission of Coordinated Universal Time, returns
hh: mm: ss continuously until CR is sent.
DATE Send date,returns
YYMMDD
UDATE Sends the date in Coordinated Universal Time, returns
YYMMDD
DJAP Send date in Japanese format, returns
YY / MM / DD
DUSA Send date in American format, returns
MM / DD / YY
DEUR Send date in European format, returns
DD-MM-YY
4DATE Send date, returns
YYYYMMDD
4UDATE Send the date as Coordinated Universal Time, returns
YYYYMMDD
LEAPSEC Leap second adjustment. Indicates if standard time will be adjusted by adding or subtracting a leap second at the next 9:00 Japan Standard Time, returns
🛆0 if there is no change
+1 if a leap second will be inserted
-1 if a leap second will be removed
LOCAL Time difference from Coordinated Universal Time, returns
+09 during normal time
+10 during daylight saving time
SUMMER Daylight saving time period, returns
0000, 0000 if daylight saving time is not applied, otherwise
MMDD, MMDD for start and end of the daylight saving time period
LOOP Enter loopback mode for delay measurement
COM Exit loopback mode
INFO Information display
HELP or ? Display a list of available commands in English
BYE or END Log off. Please use this command to terminate the connection.

Communication settings

communication method synchronous full duplex
communication speed
  • 300 bps (full-duplex CCITT V.21 BELL 103 compliant)
  • 1200 bps (full-duplex CCITT V.22 BELL 212A compliant)
  • 2400 bps (full-duplex CCITT V.22bis compliant)
  • connection mode non MNP
    data length (characters) 8 bit
    start bit 1 bit
    stop bit 1 bit
    parity none
    flow control Xon / Xoff
    local echo none
    character encoding Shift JIS or JIS
    Enter key sends only CR, no LF
    Handle received CR as CR only, no LF

    In the interest of timing accuracy, the use of error correction protocols is not recommended. However, if poor line conditions result in garbled characters, the following protocols are available. Please note that the following delays will be added in addition to the normal line delay:

    MNP4 approximately 10ms
    V.42 approximately 12ms
    MNP5 approximately 52ms
    V.42bis approximately 6 to 50ms (varies greatly)

    Transmission control codes:

    CR (return) 0Dh
    LF (line feed) 0Ah
    Xon (resume) 11h
    Xoff (stop) 13h

    Synchronization with the time signal

    The transmitted time data refers to the end of the transmitted signal. The final data frame contains the carriage return code CR, and the trailing edge of the stop bit in this final data frame marks the synchronization point with NICT's internal one-pulse-per-second (1PPS) signal.

    The reference point is the input port of the transmission modem, and the receiver needs to correct for the additional delays resulting from the transmission delay and the instrument delays of the transmitting and receiving modems.

    Timing diagram of the synchronization with the internal 1PPS signal
    Synchronization with the internal 1PPS signal