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© Sealevel Systems, Inc. 1102 Manual | SL9135 6/2021
The second method is ‘RTS Enable’ which uses Sealevel’s Windows based serial drivers to control the UART
modem control signal RTS. RTS is connected to the transmitter enable circuit and thru software control,
provides an efficient method of line-turnaround. This abstracts the application from the low-level control
and simplifies application development. This mode should be used with line termination since the
transmitter is driving the line during transmission.
The last method is
‘Data Enable’
which uses the transmitted data stream to enable the transmitter and
requires no special software drivers. When the transmitted data is a low (0), the transmitter will be enabled
to drive the line. When the transmitted data is a high (1), the transmitter will be tri-stated relying on the line
biasing resistors to pull the line to the proper state. Due to this, termination must not be used and thus data
rate and cable length are reduced accordingly.
The choice of which method to use is simple. If your data stream permits the use of the
‘Auto Enable’
mode
always use this option as it permits the simplest installation. If
‘Auto Enable’
is not an option and you are
using the IC485+ in a Windows based system, setup the transmitter control
for ‘RTS Enable’ and install
Sealevel’s
SeaCOM software. Again, if
‘Auto Enable’
is not an option, and your system is not Windows
based or if the port you are converting is not PC based, use ‘Data Enable’.
If ‘RTS Enable’ mode is chosen, begin by locat
ing, selecting and installing the correct software from the
Sealevel software driver database. Choose Asynchronous COM: Port Software, SeaCOM. Continue with the
installation until the “Setup Type” dialog, as shown below, appears. Choose “Typical (complete)” to install
the software including drivers and applications. A Start Me
nu Program Group, “SeaCOM” will be created
and WinSSD can be started from there.
