Ethernet LAN problem with ethernet cable

hello

i have a installed a ethernet straight thru cable of 30m lenght to add a
wifi access point to the network of my association.
i have tested the cable with a rj45 cable tester the cable is good no
short-circuit no cross pair

whent i connect the access point, the LAN LEd light for 10s, is off for
10s and retrun light for 10s continuously

i have connected my notebook (with Xp and Linux) in 2s an IP is assigned
to the ethernet card and i have access to network an Internet.

connecting other laptop and notebook, No network and no IP

Replacing the AP by a switch, same problem with LED and no network

the other point of the cable is connected to a Inventel LiveBoc Pro from
Orange.fr

removing the livebox and replacing it with a swich same problem...

i have try to connect one point of the cable to a mdi-x port of a
switch. the LED blink quickly continously but no IP is assigned to the
device connected to the switch


does anybody has an idee for fixing this problem

Thanks and sorry for my bad english
Claude

Who made the cable?  Are the plugs factory crimped?


Most of these devices are simple continuity testers.
They cannot detect a _split_ pair.  Pairing matters with the
balanced differential signalling ethernet relies upon to
run at such high frequencies.  Electrons may be color-blind,
but they know who their dance [twist] partners are.

-- Robert