II. Panel andsignal indicators
There are 11 indicator lightson the frontpanel of UT-1208H,
and on theback panel there are 1 5-pinterminal for RS-485 or
RS-232 input and8 ports 3-pin terminals for photoelectrical
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 -3rdpins
of the 5-PINterminals, and RS-485 interface
for the 4th 5th pins ofthe 5-PIN terminals.
3. Transmissionmedia: twisted-pair cable or shielded cable.
4. Working mode: asynchronoushalf-duplex.
5. Signal indication:12 signal indicator including power (PWR),
send(TXD), receive(RXD) andfailure(E1-E8).
6. Isolation degree:a isolation voltage of 2,500V RMS500VDC
non-stop and DC/DCisolation module.
7. Transmissionrate: 300BPS-115.2K.
8. Protection grade:RS-232 interface 15KVESD protection,
RS-485 interface 1,500Wlighting strike surge
protection for eachline.
9. Transmissiondistance: 0-5km (115,200-300BPS)
10.Measurements: 210mmX130mmX33mm
11.Workingenvironment: -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-stopinside design UT-1208H is
a RS-485 bus splitting hubspecially designed tomeet the requirements
of RS-485 undersophisticated electromagnetic fieldenvironment.
A transmissionrate as highas 115.2 KBPS is supported by this
product.What'smore photoelectrical isolation technology is
adopted for RS-485interface to avoidinduction of lightingor surge
into the converterand equipments tomake sure the safety and
reliability of signaltransmission. The built-inphotoelectrical
isolator and the1,500W surge protection circuit canprovide a
high isolation voltageof 2,500V for an efficient restriction of
lighting and ESD, and at the same time, lighting strike and
grounding interference can be reduced tothe least extent.This
product is suitable for outdoors engineering with adoptionof
outside switch powersupply.
Under RS-485 mode the determination circuit adopted can
determine the direct ion of the data streamand switch the control
circuit on a automatic basis for an very easy solution ofthe long-
existed transmission delayof RS-485. Thetransmission distance
is as far as 1,200 meters with a very stable performance. This
product is widelyused in expressway toll system road monitoring
system and electricitymonitoring system with nice performance
and competitive price.
RS-485 star topology bus connection is provided by UT-1208H
RS-485 HUB. Short circuit and opencircuit is providedfor all
the terminals. Photo electrical isolationof 2,500V isprovided.
Re-constru ction of RS-485 bus structure and network range
splitting can beeasily realized toimprove communication reliability.
In the caseof lighting strike or equipment failure the affected
range shall beisolated to make sure the normalfunction of other
ranges. This feature can increasegreatly the reliabilityof existing
RS-485 with achievementof shorter timefor network maintenance.
Proper application ofUT-1208H RS-485 HUB can help you with
a nice designof 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-
23
14
485+ 485-
SGND
23
1
Interpretation of frontpanel indicators:
PWR--Power, greenfor power on.
TXD--Data sending indication,green for normal
transmission from INPUTport to OUTPUTports 1-8.
RXD--Data receiving indication,yellow for normal
transmission from OUTPUTports 1-8 toINPUT port.
E1-E8--Failure alarm indicatorsfor ports 1-8, the lights
stay ON toindicate short circuit or wrong signal
connection of ports1-8. E1 is for port 1,E2 for port
2, and soon. Problems can be determined bythe 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/R8+
T/R8
GND
T/R7+
T/R7
GND
T/R6+
T/R6
GND
T/R5+
T/R5
GND
T/R4+
T/R4
GND
T/R3+
T/R3
GND
T/R2+
T/R2
GND
T/R1+
T/R1
GND
RS-485 PORT RS-232/485
TXD
RXD
SGND
485+
485
PWR2
