After playing with Treo 300, Scott's great WirelessModem and Windows XP via IrComm, I've found the following things regarding connection speed.

If the file size is 250K, the downloading speed is very good - 90 to 110 kbps. This is still slower than the 100-140k I usually got with Samsung A500 phone, but is obviously very good and much faster than the 40-50k I got with LG 5350.

However, if the file size is increased to 850K, the downloading speed decreases dramatically, down to 40-50Kbps.

So my question is why the speed getting much slower after the first ~100k downloading? Scott, do you use such a buffer size in WM? If this "slowing down" is on the IrComm side, then I'm going to develop the USB driver. If it is on the WM side, then a USB driver won't help. I intend to believe it is the phone (Treo), because I saw exactly the same behavor on LG 5350.

Some background info about the tests. As reported speed from webites such as dslreports.com are not so true, I do speed test by downloading a compressed (zip) file from a local server that I know is not busy. I use the SPCS software modem instead of 56K V90. IP header compression and hardware control options make no difference on speed. The speed on Windows 2000 is slightly slower than on XP, 70-90K (250K file downloading) and 30-40K (850K file downloading).

Overall I'm very happy with Treo 300 and WM. For a guy like me - data first, voice second, nothing beats this combination and I can now really enjoy the $40 paid monthly (I almost never use any air minutes). Technically, I, as a geek, still want to push the speed to the limit. Scott, keep up the good work!

For the USB driver, I see the Treo 300 appear in device manager as a Handspring Handheld device (PalmUSBD.sys). Should the to-be-developed USB driver simly emulate a serial-port or usb-modem and pass every byte to PalmUSBD.sys or to USB port directly?