IRIG Timecode - IRIG J Time Code

IRIG J Time Code

IRIG standard 212-00 defines a different time-code, based on RS-232-style asynchronous serial communication. The time code consists of ASCII characters, each transmitted as 10 bits:

  • 1 start bit
  • 7 data bits
  • 1 odd parity bit
  • 1 stop bit

The on-time marker is the leading edge of the first start bit.

IRIG J-1 time code consists of 15 characters (150 bit times), sent once per second at a baud rate of 300 or greater:

DDD:HH:MM:SS
  • SOH is the ASCII "start of header" code, with binary value 0x01.
  • DDD is the day of year, from 1 to 365 (or 366 in leap years).
  • HH, MM and SS are the time of the start bit.
  • The code is terminated by a CRLF pair.

At the end of the time code, the serial line is idle until the start of the next code. There is no idle time between other characters.

IRIG J-2 time code consists of 17 characters (170 bit times), send 10 times per second at a baud rate of 2400 or greater:

DDD:HH:MM:SS.S

This is the same, except that tenths of seconds are included.

The full time code specification is of the form "IRIG J-xy", where x denotes the variant, and y denotes a baud rate of 75×2y.

Normally used combinations are J-12 through J-14 (300, 600, and 1200 baud), and J-25 through J-29 (2400 through 38400 baud).

Read more about this topic:  IRIG Timecode

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    The mind that knows it is destroyed by time.
    Wallace Stevens (1879–1955)

    Many people will say to working mothers, in effect, “I don’t think you can have it all.” The phrase for “have it all” is code for “have your cake and eat it too.” What these people really mean is that achievement in the workplace has always come at a price—usually a significant personal price; conversely, women who stayed home with their children were seen as having sacrificed a great deal of their own ambition for their families.
    Anne C. Weisberg (20th century)