encode day of year, 35-38 encode tens of days, and bits 40–41 encode hundreds of days (1–366) Bits 45–48 encode tenths of seconds (0–9) Bits 50–53 encode years, and bits 55–58 encode tens of years (0–99) Bits 80–88 and 90–97 encode "straight binary seconds" since 00:00 on the current day (0–86399, not BCD) In IRIG G, bits 50–53 encode hundredths of seconds, and the years are encoded in bits 60–68. Not all formats include all fields. Obviously those formats with 60-bit frames omit the straight binary seconds fields, and digits representing divisions less than one frame time (everything below hours, in the case of IRIG D) are always transmitted as 0. No parity or check bits are included. Error detection can be achieved by comparing consecutive frames to see if they encode consecutive timestamps. Unassigned 9-bit fields between consecutive marker bits are available for user-defined "control functions". For example, the IEEE 1344 standard defines functions for bits 60–75. IRIG timecode IRIG J timecode IRIG standard 212-00 defines a different time-code, based on RS-232-style asynchronous serial communication. The timecode 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 timecode consists of 15 characters (150 bit times), sent once per second at a baud rate of 300 or greater: <SOH>DDD:HH:MM:SS<CR><LF> SOH is the ASCII "start of header" code, with binary value 0x01. DDD is the ordinal date (day of year), from 1 to 366. HH, MM and SS are the time of the start bit. The code is terminated by a CR+LF pair. At the end of the timecode, the serial line is idle until the start of the next code. There is no idle time between other characters. IRIG J-2 timecode consists of 17 characters (170 bit times), sent 10 times per second at a baud rate of 2400 or greater: <SOH>DDD:HH:MM:SS.S<CR><LF> This is the same, except that tenths of seconds are included. The full-timecode 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). See also Precision Time Protocol Network Time Protocol SMPTE timecode References Sources External links IRIG information — IRIG information