II. Panel and signal indicators
There are 11 indicator lights on the front panel of UT-1208H,
and on the back panel there are 1 5-pin terminal for RS-485 or
RS-232 input and 8 ports 3-pin terminals for photo electrical
isolation input ports.
II. Parameters
1. Interface features: compatible with RS-232C and RS-485
standards of EIA/TIA.
2. Electric interface: RS-232C interface for the 1st -3rd pins
of the 5-PIN terminals, and RS-485 interface
for the 4th 5th pins of the 5-PIN terminals.
3. Transmission media: twisted-pair cable or shielded cable.
4. Working mode: asynchronous half-duplex.
5. Signal indication: 12 signal indicator including power (PWR),
send(TXD), receive(RXD) and failure(E1-E8).
6. Isolation degree: a isolation voltage of 2,500V RMS 500VDC
non-stop and DC/DC isolation module.
7. Transmission rate: 300BPS-115.2K.
8. Protection grade: RS-232 interface 15KV ESD protection,
RS-485 interface 1,500W lighting strike surge
protection for each line.
9. Transmission distance: 0-5km (115,200-300BPS)
10.Measurements: 210mmX130mmX33mm
11.Working environment: -40
to 80
relative humidity 5% to 95%.
Figure 1. Front Panel of UT-1208H
Figure 1. Back Panel of UT-1208H
1
2
3
With a double-core and non-stop inside design
UT-1208H is
a RS-485 bus splitting hub specially designed to meet the requirements
of RS-485 under sophisticated electromagnetic field environment.
A transmission rate as high as 115.2 KBPS is supported by this
product. What's more
photoelectrical isolation technology is
adopted for RS-485 interface to avoid induction of lighting or surge
into the converter and equipments to make sure the safety and
reliability of signal transmission. The built-inphotoelectrical
isolator and the 1,500W surge protection circuit can provide a
high isolation voltage of 2,500V for an efficient restriction of
lighting and ESD, and at the same time, lighting strike and
grounding interference can be reduced to the least extent. This
product is suitable for outdoors engineering with adoption of
outside switch power supply.
Under RS-485 mode
the determination circuit adopted can
determine the direct ion of the data stream and switch the control
circuit on a automatic basis for an very easy solution of the long-
existed transmission delay of RS-485. The transmission distance
is as far as 1,200 meters with a very stable performance. This
product is widely used in express way toll system road monitoring
system and electricity monitoring system with nice performance
and competitive price.
RS-485 star topology bus connection is provided by UT-1208H
RS-485 HUB. Short circuit and open circuit is provided for all
the terminals. Photo electrical isolation of 2,500V is provided.
Re-constru ction of RS-485 bus structure and network range
splitting can be easily realized to improve communication reliability.
In the case of lighting strike or equipment failure the affected
range shall be isolated to make sure the normal function of other
ranges. This feature can increase greatly the reliability of existing
RS-485 with achievement of shorter time for network maintenance.
Proper application of UT-1208H RS-485 HUB can help you with
a nice design of RS-48 system of high stability.
UT-1208H 8-PORT RS-485 HUB
USER MANUAL
I. Summary
IV. Electric interfaces and definitions:
RS-232C/RS-485 definition
TXD
RXD
SGND
5
485+
485-
2
3
1
4
485+ 485- SGND
2 3
1
Interpretation of front panel indicators:
PWR--Power, green for power on.
TXD--Data sending indication, green for normal
transmission from INPUT port to OUTPUT ports 1-8.
RXD--Data receiving indication, yellow for normal
transmission from OUTPUT ports 1-8 to INPUT port.
E1-E8--Failure alarm indicators for ports 1-8, the lights
stay ON to indicate short circuit or wrong signal
connection of ports 1-8. E1 is for port 1, E2 for port
2, and so on. Problems can be determined by the user
according to different light indicators.
Fig 3. RS-232C/RS-485 input interface
Fig 4. RS-485 output interface
1.RS-232C/RS-485 input interface definition
2.RS-485 output interface definition
5-PIN Terminal Interface
1
2
3
RS-485
485+
485-
GND
5-PIN Terminal Interface
1
2
3
4
5
Signal Direction
OUT
IN
Definition
TXD
RXD
SGND
485+
485-
MODEL:UT-1208H
8-PORT RS-485 ISOLATED HUB
PWR1
TXD
RXD
E7
E5
E3
E2
E8
E6
E4
E1
DC9-48V
T
/R
8
+
T
/R
8
G
N
D
T
/R
7
+
T
/R
7
G
N
D
T
/R
6
+
T
/R
6
G
N
D
T
/R
5
+
T
/R
5
G
N
D
T
/R
4
+
T
/R
4
G
N
D
T
/R
3
+
T
/R
3
G
N
D
T
/R
2
+
T
/R
2
G
N
D
T
/R
1
+
T
/R
1
G
N
D
RS-485 PORT
RS-232/485
T
X
D
R
X
D
S
G
N
D
4
8
5
+
4
8
5
PWR2
