KIM-1 - Tape Format

Tape Format

Each bit is represented by three 2.484 ms long tones. The first is always 3700 Hz, the middle is 3700 Hz for "0" or 2400 Hz for "1", and the last one is always 2400 Hz. This gives an effective bit rate of 134.2 bit/s. Detection is done through a PLL using LM565.

The format of data on the tape is: 100 bytes with the value 0x16 (SYN, Synchronous Idle), one byte with the value 0x2A (*), the record identification number, the start address (two characters for the low byte of address, two characters for the high byte), the end address (in the same format), the actual data, one byte with the value 0x2F ("/" character ), a two-byte checksum, and two bytes with the value 0x04 (EOT, End Of Transmission).

Each byte of memory is stored as two sequential ASCII characters on tape, for example, hexadecimal B5 in memory (181 decimal) would be stored as two sequential ASCII characters "B" and "5" (42 and 35 hexadecimal).