Connecting HP48G to WinXP PC thru USB


I was wondering if anyone has had any experience/success/failure with using a serial-to-USB adapter cable (with appropriate driver) to connect an HP48G/GX to a PC via a USB port. (I know the HP49 series has USB connectivity intrinsic to it, but I am referring to "old school" here.)

I am awaiting arrival for such an adapter cable in the mail, as I would like to try to hook up my HP48G to a computer with no serial port but several USB 2.0 ports. I am wondering if I have wasted my money, since the set up menus for hp48 explorer seem to offer only COM ports, not USB ports, as options. Perhaps the software for the serial-to-USB cable emulates a serial COM port thru one of the USB ports?

If this fails, can an HP48G "talk" to a PC through the parallel port using a serial/parallel adapter? I do have a parallel port on the PC in question.




As there is a person on ebay selling the usb to serial adapter with the 48G connector in place of the standard 9 pin serial, I'm guessing that it works.


As there is a person on ebay selling the usb to serial adapter with the 48G connector in place of the standard 9 pin serial, I'm guessing that it works.

Of course, the fact that he's selling it may indicate that it does NOT work :-)


True, however since it is being sold as a kit with a cd-rom that includes transfer software I suspect that it work.



it works.

However you build your own USB-HP48 connectivity

by using a standard USB-RS232 converter.

Most of them seem to have a Prolific chipset.

Just be sure to use the latest drivers.

Once the installer has bound the

USB adapter to a virtual RS232 port,

you can transparently use KERMIT or GSZ to

transfer data between the HP-48 and the PC.

I use a Sitecom brand USB-Serial adapter,

which is a small dongle with a short cable

connction between the USB and serial ports.

Very handy, and simply works:-)



Under Windows XP, a COM port will appear in your hardware menu. Thus, the programs which use COM ports will still work. All that is required is that you have working drivers for your USB-serial adaptor.

Under Linux, the adaptor should be detected automatically if it is name-brand adaptor and not homemade.


I have learned I need to take first things first!

I just got a cable from this source:

Other purchasers (and I hope they aren't "shills") sing the praises of the device and of the seller (in fairness, the seller to date has been very good, and does offer full tech support).

But I will be darned if I can get this thing to work. I have ensured that the calc and port parameters match, but I cannot get my WinXP PC to "see" my HP48G either thru Kermit or HP48 Explorer. Indeed, in the latter case it takes no time before a I get a timeout error ("There was a communications error (-3)")!

I know that one takes chances with buying generic rather than HP equipment, but something tells me the cable is fine and my setup is off.

Does anyone have any war stories to share about troubleshooting this sort of thing? In particular, I am worried that something is wrong with my calculator's communcition abilities. Any idea how I test that?



Does WinXP "see" an extra COM port as a device now?

I use a USB/RS-232 converter, but with Win98SE instead of WinXP.
Normally, I use the converter for a connection to my UPS, and the
built-in RS-232 port for the calculators. Mine has a Prolific
chipset, and there were issues with the earlier drivers. MS-DOS
Kermit can't use the special COM port, but HyperTerminal PE can
use it for Kermit, Xmodem, "Capture text", and "Send text file"
just fine. It mostly works with HPComm and Conn4x (the
"Connectivity Kits" for the 48 and 49 series), but, if I recall
correctly, the "Screen Capture" features of these won't work with

I also have an RS-232/IrDA converter that works with a built-in
COM port, but apparently can't get enough power from the
USB/RS-232 converter.



I was able to get intermittent connectivity on through the serial port on my work computer, an older IBM T30. But still, I occasion get a time out error, and when HP48 explorer finds my calculator, which isn't always, uploading or downloading attempts trigger a "Received Unexpected Packet" error.

The sell and I suspect that the cable is faulty, so we are meeting together with computers and laptops to work out a solution.

I will keep folks posted, and I look forward to any further advice and feedback.

Note that at present I am just trying to get this thing to work thru a serial port--forgetting about USB conversion for now.



I have just asked the seller to send me a replacement. Definitely a cable issue. If I hold my tongue right, HP48 explorer will allow detection and transfer, sometimes.

I really hope I haven't buggered my calc with all of this wiggling and twisting trying to get a reliable connection. I have repeatedly conducted the ON-D-PRG serial loop back test, and it passes, so I hope this is a good sign. Would that test pass if I botched the serial port?



Hello Les,

Sorry for showing up a bit late on this thread.

It just happens that a few weeks ago I was exactly in the same case as yours : I own a PC Laptop ( IBM THINKPAD type 2373 which has no COM Ports but has - among others - 2 USB Ports ) with WINDOWS XP Professionnal and I definitely needed to exchange data between my HP48GX and my laptop.

So I purchased a USB to Serial Adapter - Registered Brand/Trade name is "Prolific" - which comes with a CD ROM with Software and Manuals for various applications including USB-SERIAL Adapter. ( ... and BTW it also includes the required data for "USB-PARALLEL PRINTER CABLE" ).

I was unable to install the software myself - I am extremely bad at doing so !!!! - but my Son Olivier did it in less than 15 minutes and it works very well. The only noticeable point I would mention here is that , on my Laptop, for some unknown reason to me, this USB-COM adaptor only works with Port 2 and NOT Port 1.

To summarize, I am extremely happy with the way it works. See also in a recent post my mention of this :

I also requested help on this very same forum some 12 months ago and a forum member very kindly indicated to me the following link :


Through a bit of further research and I also found the following links : here , here and

Hopefully I can be of some help, but there are other people much better qualified than me to address this subject.

Good Luck and Best Regards


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