Re: (PMOD) Virtual UARTS (was Emachines/Etowers)
Don Lashier (dl@newportnet.com)
Wed, 23 Jun 1999 23:58:15 -0700
Internal modems have not used actual UARTs for years. They typically
use custom gate arrays that emulate a UART. There is really no reason
for a real UART, and in fact real advantages to emulating one. Speed,
for instance. The card is on the bus and its possible to clock data
in a lot faster than 115k. The FIFO buffer can also be a lot deeper
than a real UART. I think on the old Intel modems the buffer was
effectively 64k. This is the reason that internal modems usually have
a slight performance advantage of externals - basically nearly zero
latency on the serial link.
Don
On 6/23/99, at 10:11 PM, Me, Myself, &I wrote:
>Interestingly enough, in this FAQ they claim that "When the UART speed of
>8250 is reported, this is erroneous." Aparently they use a virtual UART,
>so we now have a modem that not only farms off the processing of signals,
>it also doesn't even have a real 16550 UART.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Don Lashier dl@newportnet.com
Newport Internet http://www.newportnet.com/
-
To unsubscribe, email 'majordomo@livingston.com' with
'unsubscribe portmaster-modems' in the body of the message.