User manual
  Chapter 3: Software Installation - DOS  3-3 
Echo User's Manual, ver. 0.00 
DFLEX.SYS 
DLEX.SYS is a device driver that allows you to set port 
addresses for software access of up to 32 ports . To install the 
device driver, add the following command to your
 CONFIG.SYS 
file: 
DEVICE = DFLEX.SYS [options] 
Where
 [options] are: 
P=hhh 
hhh
 specifies the I/O address of the ST16C554 
UART. 
N=d 
this parameter specifies an offset for the 
communication port numbers to start at. 
D=name 
this parameter changes the name of the ports to 
something other than COM. 
Note: You must specify at least one option 
Example 1: 
( com1 .. com8 ) 
DEVICE=DFLEX.SYS P=3f8 P=2f8 P=210 P=218 P=220 P=228 P=230 P=238 
Example 2: 
( com3 .. com10 ) 
DEVICE= DFLEX.SYS P=200 P=208 P=210 P=218 P=220 P=228 P=230 
P=238 N=3 
Example 3: 
( serial1 .. serial8 ) 
DEVICE= DFLEX.SYS P=330 P=338 P=340 P=348 P=350 P=358 P=360 
P=368 D=SERIAL 
CTIMODE 
The
 CTIMODE command allows you to configure the extra serial 
ports. It is used with the
 COM name: 
CTIMODE COMn:baud,parity,databits,stopbits 
Accessing Ports 
You can access the ST16C554 UARTS from DOS through the 
driver
 DLFEX.SYS. We provide two methods of access; character 
device access and software interrupt 14h access. 










