The 88972250 is a Modbus RS-485 (slave) communication expansion module designed as a sandwich extension for Millenium 3 controllers. It enables connectivity between one or several Millenium 3 units and external devices such as touch screens, supervision PCs, or network gateways, facilitating the exchange of input/output states and internal values. The module supports standard Modbus RTU or ASCII protocols with transmission rates from 1200 to 57600 Bauds, configurable parity (none, even, or odd), and addressing from 1 to 247, with a maximum network cable length of 1000 m at 9600 Baud using AWG 26 wire. Operating over a temperature range of -20°C to +55°C (-40°C in non-ventilated enclosures), it is powered via the 24 V controller and features UL and CSA certifications. This module is ideal for industrial automation applications requiring reliable serial communication and synchronized time updates across multiple controllers.