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OT: UTP Cat-5E
Message
From
13/12/2003 12:38:31
 
 
To
13/12/2003 12:34:36
General information
Forum:
Visual FoxPro
Category:
Troubleshooting
Title:
Miscellaneous
Thread ID:
00858872
Message ID:
00858921
Views:
23
Yet...! Oh, I can't wait for the future :-)

>Yes, we can agree on "you do what you have to" to get things working. In old structures, sometimes you just can't get from A to B readily, and those spare pairs can be a life saver. Today, wireless comes to the rescue. But that is a far cry from 1000 Mb ;-)
>
>>Yes, then we yotally agree. However, sometimes you don't have the option of installing a new cable, or it will be very expensive. Then it nice to know that you have the option of splitting the wire. I know from personal experience that splitting a 4-pair cable into 2x100MB work fine.
>>
>>And in my home I had, untill recently, many 4-pair UTP5 cables where I had two pairs for 100MB and the other two pairs were connected to separate anlogue phone lines. Worked fine for 5-6 years until I installed 1GB at homne also. At the same time I also replaced my telephone with a wireless PABX, so I did't need the analogue connections at all. By the way, in Norway the ring voltage for analogue telephone lines is 48VAC (I should know, I have worked with it close to 30 years).
>>
>>>You are correct, in 100BT you only use 2 pairs. My point was that using the extra 2 for phone service can provide mixed results. Try a POTS line on pins 4 and 5, with 90 VAC of ring voltage. Now, some US PBX's use digital on a single pair, and you may get away with that in most cases. Would I recommend it? Never. Wire is too cheap :-)
>>>
>>>>Hi Jim
>>>>
>>>>As I said earlier, I may be wrong about the 1GB (I think I am right), but for 100MB I am 110% sure that you only need 2 pairs. It may be that the specs say you must use 4 pairs, but if so it is very strange that only pin 1,2,3 and 8 are used in all the equipments I have seen. In most hubs, switches and other peripheral equipment the spare pins are grounded, which is why you can not use standard patch cables if you want to share the cable with something else.
>>>>
>>>>It reminds me of the RS232-standard (well standard or standard, not a good word in this case....!) where you needed a 25-pin connectors with all pins connected in the beginning, then after a few years you only needed 9-pin connectors.
>>>>
>>>>>Hi Tore,
>>>>>
>>>>>The spec for 1000BT calls for all 4 pair - I thought you might have something else in use that got you around that. Off the shelf equipment needs 4 pair. I am surprised that you have no problems at 100 Mb splitting out pairs. Your luck is better than mine :-)
>>>>>
>>>>>>Hi again
>>>>>>
>>>>>>PLease forgive me if I am wrong, I have many computers and a mix of 100MB and 1GB. The 100MB I can positively confirm, about the 1GB I am not quite sure, but I belive it also only 2 pair? I must confess that where I have the mix of lan and PABX on the same cable, I only use 100MB. But at my office I have some offices where I needed more connections than I had prepared for, so I have splitted one connection into two, by using 2 pairs for connection one, and 2 pairs for the other connection.
>>>>>>I am almost sure I also get 1GB connection speed in those cases, but I am not willing to bet, I may be wrong.
>>>>>>
>>>>>>>Really? How are you getting 1Gb speeds without all 4 pair?
>>>>>>>
>>>>>>>>By the way, I use it in a 1GB lan, so speed is not an issue here.
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