9
W&T Plastic Fiber Optic Interfaces and Tools
Subject to error and alteration
Notes for use of the ber optic interfaces
All specifications for maximum transmission parameters refer
to operation of the interfaces on serial ports equipped with type
MC1488 RS232 drivers and at a voltage of ±12V. The specications
also presume that the handshake lines of the interface are enabled.
If the interfaces are supplied only from the data lines, and when
operating on low-eciency RS232 ports you must take into account
limitations with respect to maximum transmission length, baud rate
and temperature range.
Since maintaining of all three parameters is a direct function of the
construction of the RS232 port and a solid power supply for the
ports, and these parameters have a mutual effect, it is not possible
to suggest specic values.
Practice has shown that for RS232 ports equipped with MAX232-
compatible IC’s, no operating restrictions exist as long as the
handshake lines on the port are enabled.
Laptop ports with low output levels are however only in exceptional
cases able to provide the ber optic interfaces with sucient power.
For short distances, however (up to max. 20 meters), there is a
special power-saving version 81029, which can be purchased for
such applications.
When there are power supply problems, it is always however
possible to supply the interface converter externally through its
handshake inputs with a voltage of up to 9V, or to use ber optic
interfaces with their own power supply (such as our model 81201).
The specied minimum distance of 5 meters for the 81009 Interface
only applies if the Interface is operated on an RS232 port with high
output levels. If under these conditions a short cable length is
required, a model 81029 may also be used.
