[time-nuts] Frequency counter recommendation

[Elio Corbolante]

>
> From: "Chris Caudle"
> The problem with USB-RS232 adapters is that there is no class compliant
> device, because there is no USB class for RS232 emulators.  Doesn't exist,
> so every device you've ever seen or used is a custom USB device.  The
> drivers for the FTDI devices ship with modern variants of Windows and
> recent Linux distributions, which makes it behave essentially the same as
> a USB class compliant device, but ubiquitous is not the same as
> standardized.
>

Sorry to contradict you:
it exists and it is called CDC class:
<http://en.wikipedia.org/wiki/USB_communications_device_class<javascript:void(0);>
>
On Windows (for the the serial adapters) it was completely supported from XP
(SP2?).

If your device is _really_ CDC compliant and you have lost its "drivers" it
is enough to take the .INF file from another vendor and, with a text editor,
modify it accordingly to the VID & PID of your adapter.

If you know the inner working of .INF files, you will discover that a true
CDC class compliant device will not require any file except for the .INF
description
If the .INF will load other files (.SYS) it can be for 2 reasons:
1) the device is not really CDC compliant
2) it can work faster if used in a proprietary mode

_     Elio.