The Siemens 6ES7924-2AA20-0BA0 is a connection module for the SIMATIC S7-1500 automation system. It provides 40 screw-type terminals — 32 for I/O signals, plus 4 each for L+ and M — to break out field wiring from the front connector of a digital I/O module. The module mounts on either 35 mm or 15 mm DIN rail and accepts stranded wire from 0.5 to 2.5 mm² per connection, with a maximum of two wires per terminal using a ferrule. Rated voltage is 50 V, with a total current capacity of 2 A (1 A per terminal). This is the infeed version, meaning it includes the power supply feed-through for the I/O bus.
It mounts in any position on DIN rail. The screw terminals are at the top, single-level, requiring a 3.5 mm screwdriver blade. No end cover plate is needed. The maximum cable run between the front connector module and this connection module is 30 m. The enclosure is grey, rated for pollution degree 2 and overvoltage category II, with an operating temperature range of 0 to 60 °C and storage from -40 to +70 °C. The insulation material is rated UL 94 V-1 for flammability.