The CT2561 is a 16 MHz single chip dual redundant MIL-STD-1553 Bus Controller (BC), Remote Terminal Unit (RTU) and Bus Monitor (MT). Packaged in a hybrid plug-in or flatpack, the CT2561 performs all the functions required to interface a MIL-STD-1553 dual redundant serial data bus such as ACT4487 and a subsystem parallel three-state data bus. Using a single Aeroflex custom monolithic ASIC design, the CT2561 features pin-for-pin and functional CT2565 compatibility, user initiated self-test, and low power consumption. Compatible with most microprocessors the CT2561 provides a 16bit three-state parallel data bus and uses direct memory access (DMA type) handshaking for subsystem transfers. All message transfer timing, DMA and control lines are provided internally, thereby reducing the subsystem overhead associated with message transfers. The CT2561 implements all dual redundant MIL-STD-1553 mode codes. In addition, any mode code may (Optionally) be legalized through the use of an external PROM. Complete error detection is provided by the CT2561 for BC and RTU operation. Error detection includes: response time-out, inter-message gaps, sync, parity, Manchester, word count and bit count. The CT2561 is fully compliant with MIL-STD-1553, is available screened in accordance with the requirements of MIL-STD-883 and operates over the full military temperature range of -55C to +125C.