The IM 461-3 interface module can be inserted into the following expansion modules:

• UR1,
• UR2,
• ER1 and
• ER2.

The module has:

• 2 LEDs for indicating faults.
• 1 interface (input) for connecting the 468-1 connecting cable of the upstream interface module.
• 1 interface (output) for connecting the 468-1 cable to the downstream interface module. At the last interface module on the line, a terminating connector must be plugged into this interface.
• Coding switch for setting the number of the rack.
• Battery infeed socket for connecting an external battery when replacing the rack power supply.