National Instruments, Media Converter, models:

GPIB-232CV	User Manual
GPIB-232CV-A	User Manual
GPIB-422CV	User Manual
GPIB-PRL	User Manual
GPIB-RS232	Installation Manual
IVN-8561	Getting Started Manual Getting Started
NI 6221	User Manual
NI GPIB-RS232	Installation Manual
NI PXI-5600	Getting Started Manual
NI PXIe-5601	Calibration Procedure
SCXI -1124	User Manual