Siemens 6ES5777-0BB00 Programmable Logic Controller Module

Siemens 6ES5777-0BB00 is a SIMATIC S5 bus terminal (BT 777-0) designed for terminating and bridging a segment of the S5 SINEC L1 fieldbus within legacy automation systems. Also known as 6ES5 777-0BB00, this BT 777-0 family member carries the market-facing listing and is documented with 6ES5777-0BB01 listed as its direct successor, with an alternate reference of 6ES5-777-0BB00 in catalogs. This part is described as discontinued, with its lifecycle ending on October 1, 2002, reflecting its role in older equipment rather than current PLC architectures. In practice, 6ES5777-0BB00 appears in Siemens and third-party catalogs as a bus-terminal component for S5 installations and is typically encountered in older networks where the BT 777-0 provides the boundary and termination for S5 I/O communications on the SINEC L1 topology. Commonly cross-referenced against other BT 777-0BB00 variants in spare catalogs, it serves technicians maintaining or restoring legacy automation systems that still rely on the S5 era’s bus terminology and hardware.