Most of the Systems from Gilderfluke & Co. use the standard known as RS-422. RS-422 allows a PC to communicate with many pieces equipment simultaneously, and/or from a distance of up to a mile.
These converters are optimized for use with PCs and Gilderfluke & Co. systems. The RS-422 serial connection is the RJ-12 connector used most of our equipment. A short RJ-12 cable is included with each converter.
Some of our systems use the serial standard known as RS-232 was the standard for all serial ports on PCs for years (before USB). RS-232 ports are limited to just a few feet of wire and a single piece equipment on each serial port. The RS-232 serial connection is the male DE-09 on the USB-RS232/422. It will plug right into a Br-MiniBrick8, Sd-50 serial cable.
Although the USB-RS232/422 supports both the RS-232 and RS-422 ports, only one should be connected at a time. If you connect both, the data will be transmitted out both ports. Data received from either port will be sent to the PC properly, so long as they don't overlap. If data arrives simultaneously, then the PC will receive gibberish.