Uotek UT-1208H User Manual

UT-1208H 8-PORT RS-485 HUB

USER MANUAL

I. Summary

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 long­existed 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.

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%.

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.

8-PORT RS-485 ISOLATED HUB

PWR1

TXD

PWR2

RXD

Figure 1. Front Panel of UT-1208H

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+

RS-485 PORT

Figure 1. Back Panel of UT-1208H

E3

E5

E1

E2

T/R3

GND

T/R2+

T/R2

E7

E8

E6

E4

TXD

GND

RXD

T/R1+

T/R1

GND

RS-232/485

SGND

485+

MODEL:UT-1208H

485

DC9-48V

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.

IV. Electric interfaces and definitions:

RS-232C/RS-485 definition

SGND

RXD

TXD

2

1

Fig 3. RS-232C/RS-485 input interface Fig 4. RS-485 output interface

485+

485-

5

4

3

485+

485-

231

SGND

1.RS-232C/RS-485 input interface definition

5-PIN Terminal Interface

1

2

3

4

5

Definition

TXD

RXD

SGND

485+

485-

2.RS-485 output interface definition

5-PIN Terminal Interface

1

2

3

Signal Direction

OUT

IN

RS-485

485+

485-

GND

1 2 3

V. Applicatios of UT-1208H 8-Port RS-485 HUB

1. Application in connection from RS-232C serial port of
main control machine to 8 RS-485 interfaces.

RS-485 device A

RS-232

Main control

machine

1
2

IP RS-232 PortIP RS-232 Port

3
4
5

( UT-1208H )

2. Application in expansion from existing RS-485 BUS to 8
RS-485 interface. A maximum of 128 RS-485 hubs can be
connected simutaneously to RS-485 BUS.

1

1

2

2

RS-485 Bus

IP RS-232 PortIP RS-232 Port

3

3

4

4

5

5

( UT-1208H )

Port 1

RS-485 device B

Port 2

RS-485 device C

Port 3

RS-485 device D

Port 4

RS-485 device E

Port 5

RS-485 device F

Port 6

RS-485 device G

Port 7

RS-485 device H

Port 8

RS-485 device A

Port 1

RS-485 device B

Port 2

RS-485 device C

Port 3

RS-485 device D

Port 4

RS-485 device E

Port 5

RS-485 device F

Port 6

RS-485 device G

Port 7

RS-485 device H

Port 8

3. Applications in connection from RS-232C serial port of main
control machine to multiple RS-485 interfaces or in expansion
from existing RS-485 BUS to multiple RS-485 interfaces and a
maximum of 128 RS-485 hubs can be connected simutaneously to
RS-485 BUS.

RS-485 device A

RS-232

Main control

machine

OR

RS-485 Bus

1
2

IP RS-232 Port

3
4

IP RS-232 Port

5

( UT-1208H )

1

1

2

2

IP RS-232 PortIP RS-232 Port

3

3

4

4

5

5

( UT-1208H )

Port 1

RS-485 device B

Port 2

RS-485 device C

Port 3

RS-485 device D

Port 4

RS-485 device E

Port 5

RS-485 device F

Port 6

RS-485 device G

Port 7

RS-485 device H

Port 8

RS-485 device A

Port 1

RS-485 device B

Port 2

RS-485 device C

Port 3

RS-485 device D

Port 4

RS-485 device E

Port 5

RS-485 device F

Port 6

RS-485 device G

Port 7

RS-485 device H

Port 8

VI. Alarm and Protection of RS-485 Port Failures

Efficient solutions of RS-485 ports failures hall greatly increase
the liability of RS-485 device connections. The short circuit protection
fuction of all the 4 ports for subordinate machine shall work under
turn-off mode. Any failure of any specific RS-485 port shall only

influence the RS-485 BUS system connected to that port all
systems connected to other ports will not be effected. Failed ports
and other devices connected can be determined easily for solution
by users based on the alarm indicators.

VII. Prtection of Power and Lighting Strike

Outside power suply of DC9-48V/AC100-240V~60/50Hz is

adopted. Never user any other un-regulated power supply to

avoid damage caused to your products.

1,500W lighting strike protection is available for all the RS-485

interfaces of UT-1208H for efficient restriction of lighting strike

and ESD. Grounding has to be ensured for a safe and stable

communicationss.

4 5 6