USB vs. Serial
There are many reasons for using Serial over USB, especially with this type of equipment.
1. Serial isolates the connection more electrically. So a problem with an external device connected via the serial port will not break the computer. Worst case it usually only hits the serial IO chip (1488/1489/or specialty chip). Most serial ports have some isolation built in.
USB on the other hand is very closely connected to the devices that it is connected to. Even providing 5 Volts at up to .5 Amps (per the spec). This is great if you want to run a small hard disk or memory stick, but not as good for the electrical isolation test equipment should have.
2. Most shops and mechanics don't have the newest equipment. Especailly in their test area. They may be running windows 95, 98 or even DOS!! Their systems don't always have USBs but always have serial ports.
3. It'* a lot easier to get a USB -> Serial cable for newer computers than to get a USB port in an older computer. Windows 95 and 98 (first edition) doesn't even support USB. You have to upgrade to MS Windows 98 (B / second edition).
PriceWatch.Com (my favorite place for low prices on computer stuff) shows many of these cables for less than $20.00.
So please don't take the fact that it uses serial over USB to mean that they are behind the times. It'* just not true and, in industrial applications, the opposite may be true!
I know that sounds backwards, but there are several new players in industrial platforms that have all the newest stuff for connectivity including bluetooth wireless networking, USB, etc. Their company'* marketing wants to promote those things as making the product better than the competition. However many of the products are junk and only sell because of the bells and whistles. When they don't work right and cost time and money due to lost production they are returned if possible and scrapped if not.
1996 Bonneville SSE (K)