The Bus Transmitter Module (BTM) permits expansion from the main CPU rack when more modules are required in a system than can be contained in the CPU rack. The BTM allows expansion from the CPU rack to a maximum of 7 additional IC697 PLC racks. It also provides a high performance parallel interface to the programming device. The module occupies a single slot and has two connectors. The top one is for attachment to the programming device. The bottom one is for a daisychained arrangement through Bus Receiver Modules to expansion racks. Three green LEDs provide status indication of each port and module status. The BTM must be configured into the IC697 PLC system using the MS-DOS or Windows programming software configuration function.