User`s guide

Chapter 6 Special Features: Software Selectable MEI 63
Set the Supported Baud Rate for Multi-drop Support
The PortServer TS 8/16 MEI requires setting a baud rate range in order to
perform the automatic transmitter control. This setting does not influence
the performance in EIA-232 mode or for EIA-422/485 configurations where
the transmitter is always on.
The range supported by default is: 50 -230400 bps
To change the supported baud rate range
1. Select System >
MEI.
2. Select Baud rate from the drop down box.
3. Select Enable all serial ports (to enable the serial port transmitter) if
appropriate.
4. Click Apply for configuration to take effect.
Four-Wire Multi-Drop Network Scenarios
There are two scenarios of devices on a four-wire multi-drop network. The
Master and the Slave. A Master has a dedicated pair of wires to talk to the
Slaves. The Slaves share a return pair to the Master and need to control
their transmitters so that only one device at a time uses that pair. Following
are the specific procedures to set up a Master or Slave MEI setting.
MEI Configuration for a Single Master:
1. Click Serial Ports > port # > MEI Serial Settings
2. Select 422/485, Tx Control > Always on.
3. Select Enable alternative pinout (altpin). This option is only enabled
with 4 Wire. See the following table for pin out information.
4. Click Apply for settings to take effect.
10 DCD CTS- (B)
Pin
Number
EIA-232
Signal
Standard 10-Pin
EIA-422/485
Signal
(4/8 Wire)
Optional 8 pin
EIA-422/485
Signal
(Alt-4-Wire)
EIA-485 Signal
(2-Wire Mode)