Digitus DA-70163 User Manual

RS-232 SERIAL INTERFACE

PHOTOELECTRIC ISOLATOR

User Manual

DA-70163

I. Summary

With adoption of advanced photoelectric isolation technology, RS-232 Serial Interface

Photoelectric Isolator, also named Serial Isolator, can offer best protection for RS-232 serial

interface devices with elimination of damages possibly caused up by grounding

loop voltage, surge, lighting induction, hot plug, etc.

Normally, RS-232 damages are hardware damages of communication devices, for which

more than 90% of the reasons are bad circumstances including non-grounding at both ends

of the devices, several surges, lighting induction, static interference, hot plug,

electromagnetic interference, etc. For example, if device A is connected to device B with

RS-232 interface, when there is a voltage margin of above 50V between their grounding

wires, the communication will gets unstable. RS-232 Serial Interface Photoelectric Isolator

can tolerate a peak voltage margin of transient 2,500 Vrms for 500VDC on a continuous

base, and at the same time, it is able to absorb static and electromagnetic interference for

protection of RS-232 devices.

As the electric and grounding loop between the two ends of RS-232 devices are completely

blocked by the advanced isolation technology adopted by us, therefore, the electric signal

from one end has been turned into optical signal for transmission to the other end, and the

optical received by the other end will be converted back into electric signal again. In this

way, the communication devices are well protected from the interference and damages

possibly caused by power grounding loop or surge, therefore, obvious improvement of the

reliability and stability of the communication system are achieved.

Our products are now being widely used in the applications of point-to-point RS-232

communication system, UNIX multi-user system, monitor control system, program control

exchanger charging terminal, satellite receiver, ATM etc for the industries of electricity,

insurance, telecommunications, railway, post office, financial, banking, securities, program

controlling, etc.

II. Technical parameters

Interface: conforming to EIA RS-232 and CCITT V2.4 asynchronic protocols

Connector: DB9 connectors for both ends

Transmission mode: Asynchronic, full duplex, full transparent

Isolation voltage: 2,500Vrms impulse or 500 VDC continues

Transmission rate: 300BPS-57, 600BPS

Power: from RS-232 interface (TXD, RTS or DTR)

Measurements: 63*33*17 mm

Weight: 30g

Working environments: -40 degrees to 85 degrees

Relative humidity: 5% to 95%

III. Connector and signal

Pin distribution at RS-232 DTE end

IV Connector and signal

Conforming to EIA RS-232 and CCITT V2.4 standards.2-3 pin for data sending and

receiving, 7-8 pin for RTS and CTS, 4-1 pin for DTR and DCD, 6 pin for DSR and 5 pin for

GND. RS-232 interface (TO DTE): Connector: DB-25/9 hole-shaped connector to be used.

Signal: interior signal cables are separated.

1. Model selection

First of all, you have to get a clear idea of which signal cables are used by your RS-232

system, then you can select the proper model isolator to protect your communication

system. For example, for the terminal of the traditional 2, 3 and 5 lines, you can select the

isolator which supports 3-line-2-cable 1-receive-1-send mode. And for the 5 line terminal of

2, 3, 4, 5 and 7, you can select the isolator which supports 5-line-4-cable 2-receive-2-send

mode.

2. Connection method

RS232 optic isolator can be connected in series with between the serial connection cable of

the previous RS-232 and the RS-232 interface, and either end is OK but you have to pay

attention to the direction indicated by TO DTE or TO DCE. Generally speaking, PC user

and multi-user are DTE devices; MODEM and terminal are DCE devices, however this

general rule dose not apply to all situations. To decide DTE or DCE devices, you have to

base your conclusion on the signal cable of your devices RS-232 interface. For example, it

is DTE for the signal output from DB25 interface pin 2, while its receiving input is DCE.

Therefore, if crossed RS-232 cable is used to connect two DTE devices (e.g. terminal and

multi-users), you have to connect the TO DTE end to the device and TO DCE end to the

cable, no matter which side, and your RS232 optic isolator is connected.

V. Application areas

 Various kinds of multi-user systems such as UNIX

 Protection of multi-user terminal and host

 Protection of satellite receiver

 Protection of multi-user cards

 Protection of ATM connected with RS-232 devices without pubic grounding

 Protection of MODEM and routers

VI. Application diagram