|
| Definitions and normative requirements
for different categories and classes of channels. |
| International standardization overview. |
| |
Copper
cabling
cat. |
Corresponding
classes |
Applications |
European
norms |
Internat.
standards |
USA
standards |
|
5,5 |
D |
Commercial
building
telecom-
-munications
cabling standard
|
EN
50 173-1 |
IS
11801 |
EIA/TIA
568-B.1 |
| 6 |
E |
EIA/TIA-
568-B.2-1 |
| C7 |
F |
None |
|
|
| |
| About the use of terms channel, classes
and categories |
| |
| Definition of a channel |
 |
|
A channel is the transmission path between equipments such
as a LAN hub and the terminal equipment...
|
|
|
According to EIA, ISO and CENELEC standards, a channel is composed
of 90 m of cable and 10 m of cords and four connectors.
|
|
|
EX : Insertion loss of a channel = Ins loss /4 connectors +
Ins loss/ 90m cable + Ins loss / 10 m cords.
It should be designed such as to satisfy a minimum required
performance class ( ex : D, E or F ) or category ( 5, 6 or 7 ) of
channel.
|
| |
| Categories and classes |
|
|
The term "category" is used in american standards
ANSI/EIA to define all the different types of channel, link and
components.
|
|
|
In ISO 11801 and EN 50 173 serie , the term "classes"
applies only for "channel", and the term "categories"
applies to components ( cables and connectors )...
Example : classe E, according to IS 11 801 and EN 50 173, is
composed of categorie 6 componants ( cables and connectors )
|
|
| |
| Comparison between different classes
of balanced cabling according to the standards, at key frequencies. |
| Length of the horizontal cable : 90 m,
length of cords and jumpers : 10 m, parameters at 20° C, impedance 100
ohms |
| Cat. |
Standard
Ref. |
Bandwidth |
Insertion
loss* |
NEXT* |
Return
loss * |
ELFEXT* |
ACR*
min
(NEXT-
IL) |
| 5 |
TIA/EIA-
568-B.1
Annex D |
100
MHz |
21,6
dB |
27,1dB |
8,0
dB |
17,0
dB |
5,5
dB |
|
5e |
TIA/EIA-
568-B.1 |
100
MHz |
24
dB |
30,1
dB |
10,0
dB |
17,4
dB |
6,1
dB |
| 6 |
568-B.2-1 |
250
MHz |
35,9
dB |
33,1
dB |
8,0
dB |
15,3
dB |
-2,8
dB |
| 7 |
NONE |
|
|
| * at the frequency corresponding to the bandwidth |
| |
| Length of the channel : 100 m,
parameters at 20 °C, impedance 100 ohms |
| Classes |
Standard
ref. |
Bandwidth |
Insertion
loss* |
NEXT* |
Return
loss * |
ELFEXT* |
ACR*
min
(NEXT- IL) |
| D |
IS
11801 |
100
MHz |
24
dB |
30,1dB |
10,0
dB |
17,4
dB |
6,1
dB |
| E
|
250
MHz |
35,9
dB |
33,1
dB |
8,0
dB |
15,3
dB |
-2,8
dB |
| F |
600
MHz |
54,6
dB |
51,2
dB |
8,0
dB |
31,3
dB |
-3,4
dB |
|
|
| * at the frequency corresponding to the bandwidth |
| |
| Length of the horizontal cabling
: 100 m, parameters at 20° C, impedance 100 ohms |
| Cat. |
Standard
re. |
Bandwith |
Insertion
loss * |
NEXT* |
Return
loss * |
ELFEXT* |
ACR*
min
(NEXT- IL) |
| D |
EN
50173-1 |
100
MHz |
24
dB |
30,1dB |
10,0
dB |
17,4
dB |
6,1
dB |
|
E |
250
MHz |
35,9
dB |
33,1
dB |
8,0
dB |
15,3
dB |
-2,8
dB |
| F |
600
MHz |
54,6
dB |
51,2
dB |
8,0
dB |
31,3
dB |
-3,4
dB |
|
|
| * at the frequency corresponding to the bandwidth |
|
| Conclusions |
|
| Les performances d’un canal de classe D selon
l’ISO et le CENELEC sont identiques à celles de la
catégorie 5e de l’EIA/TIA |
|
| Les performances d’un canal de classe E selon
l’ISO et le CENELEC sont identiques à celles de la catégorie
6 de l’ EIA/TIA |
|
| La différence de performances entre les catégories
5 et 5e de l’ EIA est infime. |
|
| Frequently asked questions ( EIA
and IEEE article extracts ) |
| |
| Do I need all the bandwidth of class
E/catégorie 6 ? |
|
| The bandwidth is defined as the highest frequency
up to which the ratio Attenuation/crosstalk is greater than
zero. |
|
| Current applications running at 1 Gb/s are pushing
the limits of class D/cat5e cabling. |
|
| As steaming media applications such as video and multi-media
become commun place, the demands for faster data rates will increase
and span new applications that will benefit from the higher bandwidth
offered by category 6. |
|
| |
| Will class E/cat 6 cabling supersede
class D/ cat 5e ? |
|
Analyst predictions indicate that 80 to 90 percent
for all new installations will be cabled with class E/ cat 6 ...
The fact
that class E/cat 6 channel requirements are backward compatible to
class D /cat5e makes it very easy for customers to choose the class
E .. |
| |
| When should I recommend or install class
E versus class D ? |
|
| It is always better to install the best cabling available, because
it is always difficult and expensive to replace cabling inside walls,
in duct under floors and other difficult place to access. |
| |
| Is there a use for class E /category
6 in the residential market ? |
|
| This class is very effective in the residential market
to support higher internet access speeds while facilitating. |
| |
| What future for the class F / category
7 ? |
|
According to the IEEE studies ,the cat 7 only
covers 0,03 °/° of the needs of the global market .
In the United States this class is not used.
In West Europe, in year 2002, it represented 1,0 °/°
of the market when optical cabling represented 1,5 °/°
; the countries concerned are : Germany, Austria, Switzerland ... |
|
|
