UltraPort Serial Adaptors User Guide
Installing under SCO OpenServer and OpenServer6
Page 59
Chapter 2 Installing drivers and host cards
(-s) Slew Rate Limiting:
The default setting for slew rate limiting is fast. This will allow higher baud
rate speeds on each EIA interface port. Slew rate limiting enabled, minimizes EMI and reduces
reflections caused by improperly terminated cables. Operation in slew rate limited mode reduces the
amplitudes of high-frequency harmonics.
(-t) Line Termination:
The line termination parameter is not changeable by the user in EIA-
232 mode. However both EIA-422 and EIA-485 modes are defaulted to terminated but can
be changed by the user if needed.
(-e) EIA-485 HDX Local Echo:
Local echo by default is set to echoon. This parameter applies only to
EIA-485 half duplex mode. All characters will be echoed to the user and transmitted across the serial
ports. Some EIA-485 applications require local echo to be enable in order to monitor the loopback
data to determine that line contention has occurred. If your application cannot handle loopback data
the local echo should be set to echooff.
(-a) EIA-485 TX Driver Control:
The default for this field is auto. When auto is set the UltraPort SI will
automatically detect the beginning and the ending of data being transmitted in order to enable and
disable the transmit line. When the field is set to rts it is the host application’s responsibility to enable
and disable the transmit line via the RTS handshake line when it wants to send data.
(-b) Auto EIA-485 Bit Delay:
By default this field is set to 0 delay. This field is only applicable if you
have configured EIA-485 TX Driver Control to AUTO. Values for this field are 0 through 15 bits.
(-h) Help:
Displays the setultrap usage screen.
The following examples show typical user applications:
etc/setultrap -f /dev/ttyz1,/dev/ttyz16 -l -lists options configured for serial ports 1 through 16.
etc/setultrap -f /dev/ttyz1,/dev/ttyz16 -m 422 -sets serial port 1 through 16 to interface type
EIA-422
etc/setultrap -f /dev/ttyz1,/dev/ttyz4 -m 485fdx -configures ports 1 to 4 to EIA-485 full duplex
etc/setultrap -f /dev/ttyz1 -m 485hdx -t term -b 5 -sets serial port ttyz1 to EIA-485 half duplex
termination enabled, control bit-delay 5
These commands may be added to a startup script to cause them to run automatically
whenever the system is started. A sample commented out startup script (etc/rc.setultrap) is
supplied with this driver.
Note
The port must be closed and then opened for the new parameters to take effect.
