Videotec TW Serie - Manual (Page 11)

EN - English - I
nstruc
tions manual
9
6.2.4 Type of cable
h The type of cable to be used is a Cat. 5e
UTP (Unshielded Twisted Pair) (defined
according to TIA/EIA 568A and ISO/
IEC 11801 standards). Using this cable
it is possible to cover long distances
(see Tab.2) and it is possible to pass
more than one video or telemetry
signal along the same cable.
It is also possible to increase the distances using
intermediate pairs of transmitters and receivers. In
this case we recommend not exceeding ¾ of the
maximum distance for the individual sector and
using at the most one intermediate pair so as not to
excessively impair the quality of the video signal.
The device also operates with other types of UTP
cable (Cat. 2 or above - 18/24 AWG – 100 ± 20 Ohm).
The performance and the quality of the video signal
depend on the cable itself and on its location.
MAIN CHARACTERISTICS OF A CAT. 5E – 100 OHM - 24
AWG CABLE AT 20 °C
Impedanc
e
(1-100 MHz) A
tt
enua
tion
(max.) N.E
.X.T
. (min)
Loop r
esistanc
e
(max.) Insula
tion
100 ± 15
ohm 21 dB/km
@ 1 Mhz 62 dB/km
@ 1 Mhz 192 ohm/
km PE
43 dB/km
@ 4 Mhz 53 dB/km
@ 4 Mhz
65 db/km
@10 Mhz 47 dB/
km @ 10
Mhz
Tab. 04 Cat. 5e – 100 Ohm UTP cable characteristics.
If necessary (only with distances close to or at the
maximum or when colour is practically absent)
enable the BURST trimmer (colour) by setting
the jumper at position A, and adjust the BURST
trimmer until the best possible colour is obtained.
If used with MDI, set for video signal
transmission over twisted pair (please refer
to MDI instruction manual), remove the J1
and J2 jumper to adjust the attenuation.
MEANING OF THE LED’S
ON OFF
GREEN LED OR
“PW ON”
OR “POWER” Powered correctly Power supply
absent
RED LED OR “
LEVEL OUT ”
OR “LEVEL” High quality video
signal Low quality or no
video signal
Tab. 03
By opening the jumper indicated by caption
BALANCE, up to 3 receivers can be connected
in cascade as shown in the picture.
Video OUT Video OUT Video OUT
A - B
RX 1
A - B
Not terminated
(BALANCE open)
RX 2
A - B
Not terminated
(BALANCE open)
RX 1
A - B
Terminated
(BALANCE closed)
Fig. 08
j On the last receiver of the chain
the jumper must remain closed. Do
not use the STUB connection.