The 6ES7902-3AG00-0AA0 is a 50-meter RS422 point-to-point connection cable for SIMATIC S7 and M7 PLC systems. Both ends are terminated with 15-pin D-Sub connectors—a plug (male) at one end and a socket (female) at the other—making this an extension cable that inserts between a CP 340, CP 341, CP 440, or CPU with integrated PtP port and the communication partner device.

When should I use the 50-meter RS422 cable?

RS422 is a differential serial standard that supports cable runs up to 1,200 meters at low data rates, so 50 meters is well within the electrical specification. This cable is the longest standard pre-assembled length in the 6ES7902-3 series and is intended for installations where the RS422 communication partner—an operator panel, a barcode scanner, a third-party controller, or a modem—is located in a separate enclosure, a different section of the machine, or an adjacent control room. Shorter variants exist at 5 meters (6ES7902-3AB00-0AA0) and 10 meters (6ES7902-3AC00-0AA0) for same-cabinet or adjacent-cabinet connections.

Important lifecycle note

Siemens has announced a product phase-out date of October 1, 2026 for the 6ES7902-3AG00-0AA0. The product remains orderable and fully supported until that date, but for new designs with a long production horizon, check the Siemens Industry Mall for the recommended successor product or consider whether the 10-meter variant (6ES7902-3AC00-0AA0) with a field-installable RS422 extension can meet the application requirements.