The Man-Machine-Communication (MMC) bus is a star net with the. 

RLSC100 MMC unit connected in the star point

The RLKJ100 ABB RK682013-BA INPUT/OUTPUT UNIT MODULE

The optional measuring unit RLIB 100 includes the negative sequence current
protection function Insc

The RLHClOO transformer unit used in REG100 and REG110 contains
five voltage and six current intermediate transformers

NIOC-01C ABB INVERTER ACS600 series of I/O board

The PFEA112-20 ABB 3BSE050091R20 Tension Electronics

Provides first 16 Digital Inputs and high accuracy Time Synch 

link to a BRC controller for Sequence of Events

SPDSI22 ABB DI Module. 16 CH, Universal, 32 Jumpers
24, 48, 125 VDC, 120 VAC

SPDSO14 ABB DO Module, 16 CH, Open Collector

SPASO11 ABB AO Module, 14 CH, Supports 4-20mA, 1-5V

SPASI23 ABB  AI Module, 16 CH, TC, mV, RTD, High Lvl