Re: Working towards something good*

[Tristan Mumford <xtristan.xmumford@xgmail.xcom>]

Michael J. Mahon wrote:

> Tristan Mumford wrote:
>> Rob Greene wrote:
>> 
>> 
>>>Tristan Mumford <xtristan.xmumford@xgmail.xcom> wrote in
>>>news:45e2bc47$0$91140$c30e37c6@lon-reader.news.telstra.net:
>>>
>>>
>>>>I chose for now to do the modem to modem connection because I need to
>>>>get data maybe 30m across the house.
>>>
>>>Out of curiosity, do you have serial ports on both sides?  You might want
>>>to investigate that instead.  Then you don't have to tinker with modems.
>>>I'm running a serial cable from my IIgs into the basement and across the
>>>house - I'd guess 60 feet or so.  My connection is 57600 without any
>>>problems.
>> 
>> 
>> I do have serial ports on both ends. Although the serial port on the PC
>> end is a precious commodity as there is only one for some reason.
> 
> There is almost certainly another one (COM2?) inside the case, with no
> connector attached to the header.
> 
>> Hm. 60' is roughly equal to 18m. And 30m is roughly 98' according to an
>> online calculator.
>> Would that pose capacitance problems?
>> I'm also a little worried that I underestimated the length. It's not a
>> large house, but the computers are on diagonally opposite corners of the
>> house.
> 
> Theoretically, the serial cable is too long, but practically, it will
> usually work, particularly if the bit rate is dropped some.


I might have to try that. Unfortunately my Big Box of Wang Mini Cables is
running a bit low, so I'll pay a visit to one of the local electrical
engineering places to price the cable.
Here's a tip people. If you need to make cabling only use hobbyist
electronics stores (Radio Shack/Tandy, DSE, Jaycar, etc) as a last resort.
Find data cabling or electrical engineering trade supply places. It works
out a tiny fraction of the price.
The place I like going to is really good. It's a Middy's. D shells and
connectors are only a few cents each. Cabling is dirt cheap too.

One of my other reasons for choosing the modems is I already have a number
of modems and more phone cable than I want to think about.

There's also a networking solution which I am going to start experimenting
with in about two weeks time. Assuming I can find what's wrong in the RS232
receiving part of my USB board. I'm just going to write a program in
something for some platform to just send some bytes of 00 and FF at a low
bitrate so I can find where the signal disappears. Visually everything is
right, but something else is afoot.
On that, I finally stopped procrastinating and wrote the uC side of the
split serial USB driver. Still needs some issues addressed though.
Basically all the processing is done on the PC side and sent using a really
shoddy protocol to the uC which handles the low level control of the USB
IC. Ie reading and writing bytes to the registers, and performing a reset.
I did this so I can easily tweak and debug code. An upshot of this though
means that if you have a serial card you can use USB.
So I'm going to get one of those $11.50 (inc postage) USB ethernet bridges,
disembowel the linux drivers to see how it works, do my own driver and
attach the uIP stack. Hehehe.
If I can actually do that I'm going to make something like the microUSB
board with a paged flash rom or something to see if I can make some sort of
bootp support. Imagine remote booting of an apple][ using a .dsk image.
Remote future though.

-- 
-----> http://members.dodo.com.au/~izabellion1/tristan/index.html <-----
=====       It's not pretty, it's not great, but it is mine.       =====