ISDN / BT home highway
brian at Awfulhak.org
Fri Oct 6 01:57:46 BST 2000
> On Tue, Oct 03, 2000 at 06:37:44PM +0100, Brian Somers wrote:
> > =
> > =
> > A TA that does the MP stuff itself isn't a great deal of use with =
> > standard 115200bps UARTs - link bandwidth is higher than DTR =
> > bandwidth.
> > =
> Is this not true of external modems as well though? I've got an interna=
> one and can regularly exceed 115200bps:
> PPP ON parish> show phy
> Name: deflink
> State: open (with carrier)
> Device: /dev/cuaa2
> Link Type: interactive
> Connect Count: 1
> Physical outq: 0
> Queued Packets: 0
> Phone Number: 1234567890
> Device List: "/dev/cuaa2"
> Characteristics: 115200bps, cs8, no parity, CTS/RTS on
> CD check delay: device specific
> Connect time: 1:00:51
> 10416974 octets in, 164815 octets out
> overall 2898 bytes/sec
> currently 115 bytes/sec in, 51 bytes/sec out (over the last 5 s=
> peak 23908 bytes/sec on Thu Oct 5 23:57:40 2000
> PPP ON parish> =
> That's 239080bps (at 10bits/byte including the stop bits), over double =
> rate of a 16650 UART, so if this was an external modem what would happe=
> Reduced transfer rates or would the modem buffer the data?
Interesting.... I guess the limitation is only on the agreed DTR =
speed between the UART and the external modem (agreed at AT time).
Your internal modem is not emulating that limitation ;-)
Brian <brian at Awfulhak.org> <brian@[uk.]FreeBSD.org=
Don't _EVER_ lose your sense of humour !
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