01010101

01010101 is an eight-bit binary string used in computing and digital electronics. As a binary number, it represents the decimal value 85 and the hexadecimal value 0x55.

In ASCII, the byte 01010101 corresponds to the capital letter U when interpreted as standard 8-bit ASCII.

The pattern is commonly used as a test or reference sequence to check data lines and signal integrity in hardware and software. As a bitmask, 0x55 has ones on the even bit positions (bits 0, 2, 4, 6) and zeros on the odd positions (bits 1, 3, 5, 7), making it useful for selecting or toggling those bit groups in byte-wide operations.

In programming and digital design, binary literals such as 0b01010101 or hexadecimal 0x55 appear in examples to demonstrate bitwise operations, masking, and color or component encoding in bytes. The alternating nature of the pattern also makes it a straightforward example for teaching concepts like bit shifts, parity, and endianness.

Beyond its technical uses, 01010101 can be encountered in discussions of data representation, where simple, repeating bit patterns help illustrate how information is stored and manipulated at the byte level.