ELOE00XZKE001
3
1.0
Introduction
RS-232 is the interface with asymmetric signals. Maximum load capacity can be
2500pF and equates to c.50m typical twisted-pair cable.
The asymmetric signals are not ideal to eliminate the influence of zero potential
differences of terminal equipments (TE and/or DTE). The TE and neutral potentials
have to be the same hence the RS-232 interface is intended to the point-to-point
connection for 15m distance.
The load impedance is to be 3-7 kilo-ohm that allows disturbing pulses to induce
into the cable even from the soft supplies.
1.1
Use of the converter
Current loop interface is resistant to electromagnetic interference
but not to
atmospheric electricity influences!
The current loop enables to span the metallic link of the resistance up to 500 Ohm
using the power supply of 12 V.
2.0
Operation principles
E00X converts TxD signal into the transmitting cable pair of the current loop and
the signal from the receiving pair into the RxD thus the full duplex connection is
carried out. In the idle mode the 20mA current flows through each current loop.
The maximum transmission rate is 115 200 bps. Control signals are not transmitted.
3.0
Installation
There are two different problems of installation to discuss: the converter and the
TE connection via the RS-232 interface and two modems interconnection.
3.1
RS-232 interface connection
The DB9F (Female) connector is used to the converter connection. The connector
is connected as the DCE (to the end device connector, the converter can be
connected directly or via the cable 1:1). Signals assignment to the contacts and
signals´ direction is in the following table:
