Hans du Plooy wrote : >External USB modems are often no more than the usual winmodem in a shell.
That's interesting, I did not know that. My understanding is that a modem that has a controller will work from Linux, with no additional driver, by being associated with an RS232 serial port. This is obviously the COM1 or COM2 if external. If internal, the Linux compatible modem will also have a UART chip so it becomes an additional COM port (COM3?). The controller must accept the Hayes command set (the "AT" commands). It used to be that external modems would always have the controller on board because obviously they could not be controlled by the ISA/PCI bus. Therefore external COM port modems were "guaranteed" to work with Linux. OTOH almost all internal modems from the late 1990's, because they are on the PC bus, can be, and *are*, controlled from a software driver - to save the cost of the controller chip (and a licence fee to Hayes?). This driver is usually only available for Windows. Earlier internal modems (think 14400 baud, ISA slot) *did* have their own controller chip. The general change to software controllers occurred about the time that PCs went from ISA to PCI slots, so PCI modems are rare. (But lots of ISA modems on e-Bay.) Hence the traditional advice to use an external modem with Linux. Only a few internal modems are still made with controllers, apparently for a bit extra speed. They are up-market models but *not* specially made for Linux! My Multitech manual waffles on about installing under Windows, but does not even mention Linux. Some seem to be aimed at server applications - ie they are the modem at the other end when you dial in. That's my understanding, anyway. Anyone, please feel to correct me if I am wrong. But now, it's interesting that as you say external USB modems may be just Winmodems. Presumable this is possible because the extra bandwidth allows software control from the PC without too much of a hit on the data transfer rate. But it means that external modems can no longer be "guaranteed" to work with Linux. This surely means, as RS232 types are superceded by USB ones, that the traditional advice to use an external modem with Linux is no longer the cure-all it once was. Presumably the same considerations apply to ADSL adaptors. Nuke PS : Sorry about the proliferation of question marks in my last post. I'm looking into the cause. See if it happens with this post too. Must be my internal modem corrupting it ;-) -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
