[aprssig] Need A GOOD USB<--> Serial Dongle? - Great Deal

Stephen H. Smith wa8lmf2 at aol.com
Fri Aug 15 10:13:17 EDT 2014

On 8/15/2014 4:55 AM, Mike George wrote:
> I agree with Bob's positive comment for real Prolific adapters.
> I have been using 2 Pluggable brand adapters:
> http://www.amazon.com/Plugable-Adapter-Prolific-PL2303HX-Chipset/dp/B00425S1H8/ref=lh_ni_t?ie=UTF8&psc=1&smid=A3HIHADV23VGU1
> for a few years now with Linux, XP, and Windows 7 machines and have never had a
> problem
> with them.

The problem is that the "fake" Prolific chips have infiltrated the global 
electronic supply chain,  and are embedded in numerous other devices such as 
"USB" GPS devices (which are actually serial internally with a built-in 
serial-to-USB conversion).  Older versions of the driver (without the 
anti-fake-chip "DRM") work.  But when Windows' automatic updates installs the 
latest version, these devices stop working, yielding the dreaded yellow 
exclamation mark in the Device Manager.

Further, Prolific has released several significantly different generations of 
their chip with significantly DIFFERENT driver requirements.  Prolific seems to 
have a policy of "forced sunsetting" of older versions of the chip, by 
non-supporting them in the latest versions of the driver bundle.

However,  they keep using THE SAME MODEL NUMBER (PL-2303) for parts with 
sharply different driver requirements.

The result is that GPS devices from various manufacturers, that include a 
"PL-2303" work with the driver provided on the included CD (This includes 
Globalsat BU353, Microsoft "GPS Locator", Holux, Pharos iGPS, etc). But again, 
when Windows Update "auto-magically" replaces the existing driver with the 
latest one for a "PL2303", these devices stop working.

It gets even worse, if you happen to use an older device (perhaps a GPS) and a 
newer device (perhaps a cable dongle to your TNC) at the same time.    The GPS 
works with the older driver, but not the TNC.  Update the driver, and now the 
TNC works, but not the GPS.  All because you can't have multiple versions of a 
driver for the "same device" ("PL2303") installed at the same time.

All because of Prolific's irresponsible action of assigning the SAME model 
number to several DIFFERENT generations of chips.

All-in-all, the PL-2303 situation is such a mess that one should just avoid 
Prolific if at all possible.   With devices using the FTDI chip now  nearly as 
cheap as ones embedding the infernal Prolific chip, there is now no reason to 
put up with the endless Prolific headaches.

(Prolific has gained such a reputation for problematic drivers that recently, 
I've noticed a trend of vendors of even cheap generic USB<-->serial dongles now 
bragging about "uses genuine FTDI chip" in their advertising.)



Stephen H. Smith    wa8lmf (at) aol.com
Skype:        WA8LMF
EchoLink:  Node #  14400  [Think bottom of the 2-meter band]
Home Page:          http://wa8lmf.net

Long-Range APRS on 30 Meters HF

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