[TowerTalk] Computer control antenna switch

Jim Lux jimlux at earthlink.net
Wed Mar 9 17:58:33 EST 2005


At 02:00 PM 3/9/2005, Pete Smith wrote:
>I thought I had read, though, that some new-generation laptops do not have 
>an LPT port.
>
>73, Pete N4ZR
>
>At 04:15 PM 3/9/2005, R. Kevin Stover wrote:
>
>>I haven't seen a mobo manufacturer come out with a product without a
>>IEEE 1284 port yet.They won't be getting rid of the parallel port
>>anytime soon. They are starting to cut out the RS-232 ports.
>>Yes, you see a lot of mobos from the manufacturers with multiple USB
>>port configurations, the machine I just built has 8, but the current USB
>>spec has some serious limitations. The 5m segment length limitation
>>being the most notable.


Indeed, For instance, the HP Tablet PC (tc1100) doesn't have a printer 
port, nor does the new tc4200.  Lots of the newer laptops don't (I'd 
estimate that perhaps half of HP's models don't have parallel ports, and 
some that do have them in a "expansion interface.. a sort of mini docking 
station)

Most of the desktop machines do seem to still have parallel ports, however, 
one wonders what they think people are going to connect to them, because 
the vast majority of printers sold today (particularly in the consumer 
market, which drives pricing and features) are USB.
(The cheapest printer HP sells that has a parallel interface is $250, 
almost as much as the cheapest computer they sell ($399))

I won't claim that HP is the only game in town, but they're certainly 
representative of the market as a whole.

Since the average ham is going to have their radios, antennas, tower, and 
all the control stuff a LOT longer than the 3 yr cycle time of a typical 
PC, it makes sense to choose a control interface that has some potential 
longevity.

Serial interfaces will probably be around for a long time, even though 
you'll need some sort of adapter to get from whatever the computer has to 
RS232.  They're just too simple and inexpensive to implement for a huge 
class of things, and because the underlying protocol is used in modems, the 
concept of a "serial bit stream" will probably be supported in future OSes 
as well. (that said, I have probably spent more hours fighting with serial 
interfaces and the code to control them than any other kind of interface)

Ethernet or some network flavor similar to it will be around for quite a 
while too. While the physical medium may change (not much Thicknet or 
Thinnet around any more), the basic comm protocol will endure for at least 
another decade or two.  This would be my choice for a low cost 
interconnection medium... does long distances (unlike USB), mass market so 
parts are cheap, etc... and it supports a variety of wiring topologies as 
well as inexpensive off the shelf high performance wireless (and not so 
inexpensive, but still off the shelf, optical fiber).





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