The board features an RS232 or COM port (CN3), an RS485 port for controlling additional power supplies with CT-551, and a connection plug (CN1) for the power supply. A maximum of 8 power supplies can be controlled for parallel operation (1 Master CT-251 and 7 Slaves CT-551 - Conrad item no. 1991946). This item consists of the control board CT-251 and the connection cable (COTEK Part no. 47-0124-0001). It allows for the regulation of the output voltage in a range of 0-105% and the output current from 0-105%. The following additional components are required to control the power supplies: COTEK AE / AEK series power supply, control board CT-551 for each additional power supply (Slave), PC or laptop with an available COM port/RS232, USB-to-RS232 adapter or USB-to-RS485 adapter, and null modem cable.