[Malvern] Connecting Equipment

[Guy Inchbald]

ian.pascoe at bt.com writes
>Gents
>
>Need someone in the know to point me in the right direction.
>
>The scenario is if you have 2 pieces of quipment running at different
>clock speeds but need to talk to one another how is it done?  I assume
>that the interface between the, say PC and LAN, has an input and output
>buffer that collates the data until the other side can pick the
>information up.  Is this right?

That's one way. Another way is to use a sync system which makes the fast
equipment wait until the slow stuff is ready for it - this tends to be
cheaper but ties the fast bit up more. Which way a particular job is
done depends on many things.
For a PC to LAN connection, the data to be transmitted is stored in
memory and then fed down the data bus to the NIC. Some NIC's then do
more buffering, handshaking with the other end and error-correction than
others.


>Does this also work on a mother board where you have the processor
>running at G Hz speeds and the data bus running at M Hz speeds?

The processor usually has a large cache memory which acts as the
required buffer. Where a cache is not present (or useable for whatever
reason) the processor has input and output buffers. Depending on the
processor, it may or may not be getting on with other things while the
buffer is talking to the external bus.

 
>Lastly, if you have a scenario of 2 detached houses with a cable linking
>both, which is used for telephony, are there any cards available which
>allows the PCs to talk together by using the spare bandwidth of the
>cable - similar to the principles used in ADSL?
>
>This is not an actual scenario but follows on from the discussions we
>had at Geoffs about his new ADSL router.

Wouldn't the best way be to use the landline for a PC-to-PC network and
do the telephony bit using VoIP? This would free up the full bandwidth
when the phone was not in use.


Cheers,
Guy Inchbald
(Lurker who's going to reinstall Linux real soon now).

-- 
Guy Inchbald