The Atkinson Electronics SM2 Trunk Interface (AETI-485/TTL2) is a TTL to TTL to RS-485 repeater module. It was designed to extend STAEFA’s TTL communication trunk by repeating STAEFA’s communications in either STAEFA’s TTL format or in a RS-485 ½ duplex format. The RS-485 format allows for communications to be extended over 2,500 feet, while the TTL repeater allows additional quantities of Smart II controllers to operate on a single system panel trunk. The AETI-485 uses an on-board isolation transformer to provide isolation between each of the TTL and RS-485 communication ports.
The AETI-485 is also available in a single TTL trunk.