One Technologica TDA 08 acquistion module for RS485 networks.You are buying new unused stock  from our clearance of a major air conditioning  manufacturer. Outer boxes may be scruffy,  TDA 08 ACQUISITION MODULES FOR RS485 NETWORKS The TDA 04 acquisition module transmitt process measurements via RS485 serial links with MODBUS RTU (JBUS) protocol to either a computer based data acquisition system or to the Tecnologic TMS01 monitoring and recording device. The TDA 0..