The OM that buys a new portable computer - without verifying the available interfaces - can have a displeasure. As you know, the new notebook models no longer have the RS-232 and Centronics (LPT) so needed to transceiver software control.

For those that have the new transceivers models with USB interface don't have any problem with these new notebooks, but for those that still have the old RS-232 interface it can be the sign for a great headache.

Of course, the experts can say that it is enough to buy a USB/RS-232 converter and the problem is solved! Are you shure?

fig. The usual USB/RS232 interfaces.

The problems

In the market there is thousands of interfaces models that, instead of solving a problem, create anothers. When we plug a new USB device is necessary to install a small software (driver) supplied by the manufacturer. The driver reserves a new free door number, not leaving alternatives to the user. More complicated is the situation when we want to share other USB interfaces like MP3 Players, Pen Disks etc. This can force us to reinstall the software again and again resulting in others COMMS numbers.

The number 5, 8 or 10 for the COMMs would not be a problem if most of the Ham Radio setup software allowed comm numbers configuration above COM4. Who uses the writelog have already verified that it is necessary to manually edit the initialization file (writelog.ini) to get COMMs above the COM 4. Those that use another software with less setup options don't have any hypotheses to work with.

The computer experts can take the risk to change the address and IRQs numbers of the COMMs, in the Windows Control Panel. Even if with sucess, this configuration doesn't solve anything, because the COMs numbers can change again whenever we plugin another USB interface.

With the intention of solving these problems, I was buying different USB/RS232 manufacturers' converters allways with the dealer promise that they will be better than the previous ones. Along two years I have collected four interfaces. I have made some tests with them that have take me to the conclusion that three of the four models locked the ports numbers above COM5. I have tested three simultaneously interfaces but only after several reinstallations, I have finally got a working condition notebook with COM5, 6 and 7.

After the installation of the three interfaces I got a new error caused by the excessive current in the converters. As you know, the notebooks USB interfaces are limited to a certain current and in case of overload, automatically turns off the device . In the test, I have verified that is not possible to work with the three interfaces (of course, I could solve the current problem using a USB HUB fed to a external 5V power suply).

Besides these problems in the serial converters I have checked that the paralell to USB convertor it is still more problematic. What I have tested doesn't allowed to switch the pins state for PTT, FSK, CW, Antennas etc., as requested by the softwares. For this interface I still didn't found a solution - at least satisfactory - and that's why I don't recommend it to any one.

All these problems can discourage any one, but happily nor everything is bad in the world of the USB converters because, one of the four tested interfaces passed with success all the tests.

The best USB interface

The Edgeport/4 was the last interface that I have acquired that have exceeded all tests. The Edgeport setup is really Plug & Play with the advantage of being easily configurable. With the edgeport it was possible to change the COMs numbers on-the-fly without communications errors and without overload currents. Finally I have configured the notebook with four RS-232 (COM1 to COM4) without headaches.

The price (263€) of the edgeport/4 (4 serial) scares any one! Happily for us, some of these equipments are already outdated and they are easy to find at good used prices.

I have made a Edgeport/4 demonstration to CT3CD and CT3EX. In one week, they got their Edgeports - for less than 50€ - from Ebay.