NIS χρήστης δεν κάνει logon στον Η/Υ

[Christos Ricudis]

Antonios Christofides wrote:

> Ρίξε λοιπόν μια ματιά στο ποια πρέπει να είναι η σωστή σειρά των 
> συρμάτων, http://twiki.itia.ntua.gr/bin/view/Main/NetworkCables, και 
> έλεγξε δειγματοληπτικά όσα καλώδια μπορείς, και πες μας τι βρίσκεις.

Kai epeidh kapoios mporei na mperdeytei, na ekshghsw ligo th diafora metaksy 
EIA/TIA 568A kai EIA/TIA 568B.

Texnika den yparxei kammia diafora. Oi dyo syndesmologies einai apolytws 
isodynames, mono pou antistrefontai ta zeygh 2 (portokali zeygos) kai 3 
(prasino zeygos).

To gegonos oti kai sta dyo protypa h syndesmologia fainetai ligo periergh, 
me to mple zeygos na "phdaei" eite to prasino eite to portokali, enw ta alla 
dyo zeygh briskontai mona tous sta akra, ofeiletai sto gegonos oti kapoios 
eksypnos skefthke oti dynhtika 8a mporouses na xrhsimopoihseis thn idia 
kalwdiwsh gia ethernet kai thlefwno. An proseksete ena RJ-11 bysma, ta dyo 
zeygh kalwdiwn einai to 2/3 kai to 1/4 (synh8ws prasino/kokkino kai 
mayro/kitrino antistoixa).

An balete ena RJ-11 akrodekth se ena RJ-45 bysma, to zeygos prasino/kokkino 
8a pesei panw sto zeygos mple/aspromple kai to zeygos mayro/kitrino 8a pesei 
panw sto zeygos asproprasino/prasino sthn periptwsh tou 568B kai sto zeygos 
asproportokali/portokali sthn periptwsh tou 568A. (An pali balete enan RJ-45 
akrodekth se ena RJ-11 bysma, 8elw na mou steilete mia fwtografia [1]).

An koitaksete to USOC protypo poy xrhsimopoieitai sthn thlefwnikh kalwdiwsh 
sthn amerikh, 8a deite oti ta dyo kentrika zeygh exoun akribws thn idia 
diataksh me to 568A.

Etsi, 8a mporousate sto patch panel sas, na parete to mple zeygos - pou 
akribws gi ayto to logo den xrhsimopoieitai apo to Ethernet - kai na to 
riksete panw sto thlefwniko sas kentro, wste na mporei h grammateas na 
bgazei ton ypologisth apo to mprizaki, na bazei to thlefwno sto idio 
mprizaki kai na antallasei syntages gia gioubarlakia me thn kouniada ths enw 
paizei pasientza, pou den apaitei th xrhsh diktyou.

H diafora twra metaksy toy 568A kai tou 568B brisketai sto DEYTERO zeygos 
toy RJ11, pou mporei na metaferei mia deyterh thlefwnikh grammh sthn 
periptwsh ths thlefwnias. To 568A exei thn idia diataksh sto deytero zeygos 
me to USOC protypo. Ayto, kapoios pou epairne POLY lhgmena narkwtika, 
skefthke oti 8a htan kalh idea, alla kanenas allos meta apo ayton den 
katafere na brei akribws thn idia partida lhgmenwn narkwtikwn gia na 
diapistwsei GIATI tou fanhke kalh idea - apo th stigmh pou to zeygos ayto 
xrhsimopoieitai KAI sthn periptwsh tou Ethernet KAI sthn periptwsh ths 
deyterhs grammhs tou thlefwnou, einai apolytws adynaton na xrhsimopoihseis 
eite to ena eite to allo, ara den yparxei logos na kratas symbatothta.

Ti mas endiaferei twra. Mas endiaferei to gegonos oti to 85.89934592% twn 
yparxontwn egkatastasewn domhmenhs kalwdiwshs, einai kalwdiwmena kata 568B.

To idio akribws isxyei gia to 83.88608% twn patch cables.

Etsi, otan rixneis mia matia se ena kalwdio kai blepeis to 
asproprasino/prasino zeygos sthn akrh aristera, exeis poly kales endeikseis 
oti to kalwdio einai crossover - kalwdiwmeno kata 568A sth mia meria kai 
kata 568B sthn allh. Gia na eisai sigouros, bebaia, prepei na koitakseis kai 
to allo akro. Alla siga mh shkw8eis na pas mexri ekei.

Egw, apo ka8arh synh8eia kai mono, protimw to 568B. Ase poy to portokali 
zeygos einai sketh kayla otan brisketai akra aristera, enw to prasino zeygos 
fainetai sketh flwria.


[1] Apo tis pio diashmes teleytaies protaseis sthn plhroforikh : "Pws de 
mpainei. An to zmprwkseis ARKETA, mpainei"



-- 
Christos Ricudis				ricudis at itc.auth.gr
Systems Administrator				+30-2310-998656
IT Support Center
Aristotle University of Thessaloniki, GREECE