Expansion modules snap onto the side of any BRX Micro PLC Unit (MPU) or BRX Remote I/O controller. Added BRX serial communications modules ($159.00) provide four isolated RS-232 ports that support communications flow control or RS-422 serial ports. Also available are BRX single-channel RS-232 (with flow control) and RS-422 Pluggable Option Modules ($49.00). Universal analog I/O modules (from $159.00) have combined current and voltage options. Universal temperature modules provide thermocouple, mV level voltage, RTD or thermistor selection with 24-bit resolution. The 4-channel combination temperature I/O expansion module ($349.00) has universal temperature inputs and analog outputs. Four-channel combination temperature input / discrete output modules ($199.00) provide universal temperature inputs and discrete sink, source or relay outputs.