Although Yokogawa does not have any official recommendation for USB to Serial converters, it is possible to use some USB to RS232 DB9 Adapter Cables. If you choose to use a laptop PC without RS232C port, please use a PCMCIA to RS232C Adapter.
Many computers today do not come with an RS232 (DB9) port, making it difficult to connect a WT210/WT230 with RS232C (DB25) port to a PC's Serial COM Port (DB9). However, there are plenty of USB ports available on the PC side. Please keep in mind that not all converters work properly. There are always slight differences in the converter hardware that may not allow these converters to work our WT210/WT230.
We would also like to add that some of our customers have had success using these USB to Serial converters.
Using the above 4 hardware pieces, one of our customers has been successful in communicating with the WT210.
Please see attached PDF for reference. These are all generic items so there may not be any identifiable model or part numbers.