I want to hook two computers together to play Nascar2 by direct
connect,but I want to know if there is away to hook them together some
other way besides using a null modem cable. I have heard it can be
done with Phone lines,if so I would like to know how to do this.
Thanks,
Kenneth
Quoted text (7 lines)
> I want to hook two computers together to play Nascar2 by direct > connect,but I want to know if there is away to hook them together some > other way besides using a null modem cable. I have heard it can be > done with Phone lines,if so I would like to know how to do this. > Thanks, > KennethQuoted text (21 lines)
>> One person answers, the other dials. This direction doesn't have to >> match the original Dial/Answer from above. >> You will find that this connection is usually just a little better than >> a regular phone connection because no phone company hardware is >> generating noise. >But, I can't figure any case in which this mechanism beats a null modem >cable. Each UART in the path will introduce additional latency; it seems >better to me to use only 2 UARTS (one per computer) rather than 4 (one >per computer and one per modem). >If the two computers are so widely separated in the same building to >require a longer line, use line drivers and run straight RS-232 (or 422) >over the physical wires, but don't throw extra modems in there... >To make it work, you'll also probably need a DC bias voltage source. (A >9 V battery is reported to work, but I've never tried it, since I've >never seen an advantage to it...) >---Jim> One person answers, the other dials. This direction doesn't have to
> match the original Dial/Answer from above.
> You will find that this connection is usually just a little better than
> a regular phone connection because no phone company hardware is
> generating noise.
But, I can't figure any case in which this mechanism beats a null modem
cable. Each UART in the path will introduce additional latency; it seems
better to me to use only 2 UARTS (one per computer) rather than 4 (one
per computer and one per modem).
If the two computers are so widely separated in the same building to
require a longer line, use line drivers and run straight RS-232 (or 422)
over the physical wires, but don't throw extra modems in there...
To make it work, you'll also probably need a DC bias voltage source. (A
9 V battery is reported to work, but I've never tried it, since I've
never seen an advantage to it...)
---Jim
Quoted text (28 lines)
> >> One person answers, the other dials. This direction doesn't have to > >> match the original Dial/Answer from above. > >> You will find that this connection is usually just a little better than > >> a regular phone connection because no phone company hardware is > >> generating noise. > >But, I can't figure any case in which this mechanism beats a null modem > >cable. Each UART in the path will introduce additional latency; it seems > >better to me to use only 2 UARTS (one per computer) rather than 4 (one > >per computer and one per modem). > >If the two computers are so widely separated in the same building to > >require a longer line, use line drivers and run straight RS-232 (or 422) > >over the physical wires, but don't throw extra modems in there... > >To make it work, you'll also probably need a DC bias voltage source. (A > >9 V battery is reported to work, but I've never tried it, since I've > >never seen an advantage to it...) > >---Jim > If I us Ethernet cards are a Null Modem Cable what is the > greatest distances the two computers can be apart and still get good > performance. > Me and may cousin live next door to each other and we have > measured it to be about 200 feet . > We want to do this in order to keep from tying the phone line > up all the time.Quoted text (7 lines)
> If I us Ethernet cards are a Null Modem Cable what is the >greatest distances the two computers can be apart and still get good >performance. > Me and may cousin live next door to each other and we have >measured it to be about 200 feet . > We want to do this in order to keep from tying the phone line >up all the time.>If the two computers are so widely separated in the same building to
>require a longer line, use line drivers and run straight RS-232 (or 422)
>over the physical wires, but don't throw extra modems in there...
Agreed, modems are out, but...
Once you pay for the line drivers your almost up to the price of the
Ethernet cards which will make it easier to hack your next door
neighbor's system so he can't beat you ;-) Oops, I meant to say that
you would have the other advantages associated with networking.
Hmm... I've provided the bias voltage and have seen quite difference.
Never tried a battery though... interesting low cost approach.
Mike Radler
Member - Hawaii Ace League http://www.dithots.org/hal
> I want to hook two computers together to play Nascar2 by direct
> connect,but I want to know if there is away to hook them together some
> other way besides using a null modem cable. I have heard it can be
> done with Phone lines,if so I would like to know how to do this.
You're somewhat asking two subtly different questions:
1. Is there a connection method other using null modem cable connected
to the serial ports?
2. Can I use phone cable as the physical cable for any solution.
1. Yes, you could use a null modem cable, or Ethernet cables (or two
honest-to-goodness modems, but that would be silly)
The Null modem cables would connect the two computers serial ports.
Ethernet cards are quite cheap, and if it's a semi-permanent condition
that you'll have two computers in the same house, I'd spring the $50-$60
or so for two cheap ethernet cards and be able to use networking in the
house for other apps than just NASCAR2 (and other null-modem cable
games) The easiest way to cable these would be using BNC connected coax
cable with appropriate terminators. This avoids having to buy a hub,
which is used with unshielded twisted pair ethernet.
2. Depending on the distance involved, phone cable can carry RS-232
(null modem) signals quite well. If you get higher quality (Cat3 or
Cat5) "phone cable (unshielded twisted pair)", it can carry ethernet
traffic (10-BaseT for Cat3 and 10-BaseT or 100-BaseT for Cat5 cable).
Cheapest and least technical competence needed is a null modem cable.
Fastest and most expensive is 2 100-Base T and a 100-BaseT hub. In
between (on all counts, but perfectly servicable, and the best "bang for
the buck" IMO) is 2 10-BaseT cards and optionally a hub (if using UTP
cables).
---Jim
Quoted text (28 lines)
>>> One person answers, the other dials. This direction doesn't have to >>> match the original Dial/Answer from above. >>> You will find that this connection is usually just a little better than >>> a regular phone connection because no phone company hardware is >>> generating noise. >>But, I can't figure any case in which this mechanism beats a null modem >>cable. Each UART in the path will introduce additional latency; it seems >>better to me to use only 2 UARTS (one per computer) rather than 4 (one >>per computer and one per modem). >>If the two computers are so widely separated in the same building to >>require a longer line, use line drivers and run straight RS-232 (or 422) >>over the physical wires, but don't throw extra modems in there... >>To make it work, you'll also probably need a DC bias voltage source. (A >>9 V battery is reported to work, but I've never tried it, since I've >>never seen an advantage to it...) >>---Jim > If I us Ethernet cards are a Null Modem Cable what is the >greatest distances the two computers can be apart and still get good >performance. > Me and may cousin live next door to each other and we have >measured it to be about 200 feet . > We want to do this in order to keep from tying the phone line >up all the time.Quoted text (7 lines)
> If I us Ethernet cards are a Null Modem Cable what is the > greatest distances the two computers can be apart and still get good > performance. > Me and may cousin live next door to each other and we have > measured it to be about 200 feet . > We want to do this in order to keep from tying the phone line > up all the time.>Cheapest and least technical competence needed is a null modem cable.
>Fastest and most expensive is 2 100-Base T and a 100-BaseT hub. In
>between (on all counts, but perfectly servicable, and the best "bang for
>the buck" IMO) is 2 10-BaseT cards and optionally a hub (if using UTP
>cables).
>---Jim
I agree with Jim. The best "bang for the buck" is two 10 Mbps cards.
Get PCI cards since the end of ISA has been announced. :-)
Just some ethernet trivia:
10 BaseT max length is 100m = 328'
10 Base2 max length is 185m = 607'
10 Base5 max length is 500m = 1,640'
10 BaseT uses Category 5 unshielded twisted pair
10 Base2 is sometimes called thinnet or cheapernet.
10 Base5 is sometimes called thicknet.
10 Base2 and 10 Base5 use coax with BNC twist on connectors between
"T" connectors for each computer with a 50 ohm terminating resistor at
each end of the network. No hub is required here. Max 30 computers.
This is usually the cheapest setup for homes and small businesses.
With 10 Base2 and 10 Base5, 10 Mbps is the only popular option.
10 BaseT usually requires a hub. I say usually, since in the special
case of exactly TWO computers, you can get a special crossover cable
made to allow TWO 10 BaseT cards to talk with each other without a
hub. This type of wiring allows 10 Mbps and 100 Mbps, depending on
the type of cards used.
Beware if you are stringing this cable across a public right of way.
I am sure there are all sorts of legal problems in that case.
--
Best Wishes!!!
Robert Huggins
Raleigh, NC
> 10 BaseT uses Category 5 unshielded twisted pair
Cat 3 meets the spec for 10-T. However, Cat-5 is so cheap that buying
Cat-3 now makes little sense. (Using existing Cat-3 stock is fine, so
long as you'll never want to go to 100MBps.)
I wasn't aware of the 30 computer limit. I also can't think of the
technical reason for it, but I'll have to check the network cabling
book...
Note however, that not all cards can successfully negotiate a connection
with another card. (Generally a problem with the Plug-n-Pray 10/100
cards that look to negotiate with a hub on card initialization.)
Also beware of grounding issues if connecting to another building.
---Jim


































