I have a friend who would like to run a second computer (laptop) from his exsisting 4 port router. The only drama I can envisage is the distance from the router to it. The router (and 'phone line) is on the ground floor of a 5 storey shop building. His laptop needs to be in his living area on the 5th floor. Total distance between the two would be about 40 mtrs.

I am sure I have read somewhere about a loss of data / no data when the transfer length is to much

Any ideas anyone

If using standard CAT 5 or CAT 6 your cable can be up to 100 meters without any problems.

I have a friend who would like to run a second computer (laptop) from his exsisting 4 port router. The only drama I can envisage is the distance from the router to it. The router (and 'phone line) is on the ground floor of a 5 storey shop building. His laptop needs to be in his living area on the 5th floor. Total distance between the two would be about 40 mtrs.

I am sure I have read somewhere about a loss of data / no data when the transfer length is to much

Any ideas anyone

If you are referring to a standard ethernet line then the max distance with CAT5 cable is 100 meters. CAT5e would be a better choice due to being higher grade but not a large cost difference. I've run 94 meters between two buildings running CAT5e and running 100mbps ethernet with no problem.

No problem with the lenght! But I wou;d consider to use STP (Shielded Twisted Pair) instead of UTP (Un-Shielded Twisted Pair) because of the may available power lines and others in the Building!

I wouldn't worry about interference especially when UTP cables already have differential pairs and it's not an industrial (e.g. factory) environment. You wouldn't also have to worry about grounding the shield (I think). But that's just me..

Coincidentally, I asked what I believe amounted to the same question - though in my case the distance from the modem to my laptop wouldn't need to be anything like 100 metres.

However I am totally ignorant of the technical terms' meaning. Can you please tell me in layman's terms how to identify the right sort of cable (cat5 et al) when I ask for it or pick it up at a shop?

CAT5

The above should explain it. For home type use you really only need to be concerned that it is a direct (straight through) cable (if using router) rather than the cross-over type that you would run from one computer to another.

Actually with most routers nowadays, it doesn't really matter if it is cross-over or straight through, as most of them have "auto switching" ports.

Brilliant

Thank you all. I'll pass that on so he can go ahead and get it sorted out.