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GTEK BBS-550 with Linux mini-HOWTO

by Wajihuddin Ahmed <>

v1.1, 20 August 1997

GTEK's BBS-550 is a 8-port serial card with 16C550 UARTS. Only one IRQ can be used for all 8 ports. It does not require any driver on Linux therefore the kernel does not have to be recompiled but the kernel should have serial support.

1. What I/O addresses to use?
2. The rc.serial file and IRQ selection
3. Setup of uugetty
4. Final checking...

1. For detailed information of configuring serial ports on Linux refer to the Serial-HOWTO. Thats where I started from.

I have setup the BBS-550 to use I/O address from 0x100 to 0x140 on my Linux box (Slackware 2.3, kernel 1.3.93). The main reason being that the above address space was vacant in my computer. Page 4 of the manual gives the jumper settings. Also this range of I/O addresses is seldom used by any other hardware. Just to make sure that this space is available on your machine, use the IOMAP.EXE utility which is on the GTEK floppy disk.

2. After you have installed the card on your computer you need to configure the serial ports. This is quite easy since the rc.serial file already has entries for BOCA 8 port card which can be used for the GTEK. Here is my rc.serial file. Don't forget to execute it from the rc.S file by uncommenting the line that executes it.


# /etc/rc.serial
# Initializes the serial ports on your system
# Version 2.01
cd /dev
SETSERIAL="/bin/setserial -a"
PORTS=`echo cua? cua??`
echo -n "Configuring serial ports...."  
# Do wild interrupt detection
# Do AUTOMATIC_IRQ probing
${SETSERIAL} /dev/cua16 uart 16550A port 0x100 irq 5
${SETSERIAL} /dev/cua17 uart 16550A port 0x108 irq 5
${SETSERIAL} /dev/cua18 uart 16550A port 0x110 irq 5
${SETSERIAL} /dev/cua19 uart 16550A port 0x118 irq 5
${SETSERIAL} /dev/cua20 uart 16550A port 0x120 irq 5
#${SETSERIAL} /dev/cua21 uart 16550A port 0x128 irq 5
#${SETSERIAL} /dev/cua22 uart 16550A port 0x130 irq 5
#${SETSERIAL} /dev/cua23 uart 16550A port 0x138 irq 5
echo "done."


Notice that i have used IRQ 5. Refer to page 6 of the GTEK manual on howto set the IRQ.

3. I am using uugetty for dial-in's. Here is an extract from my /etc/inittab file (sys V).


s1:45:respawn:/sbin/uugetty ttyS16 38400 vt100
s2:45:respawn:/sbin/uugetty ttyS17 38400 vt100
s3:45:respawn:/sbin/uugetty ttyS18 38400 vt100
s4:45:respawn:/sbin/uugetty ttyS19 38400 vt100
s5:45:respawn:/sbin/uugetty ttyS20 57600 vt100
#s6:45:respawn:/sbin/uugetty ttyS21 38400 vt100
#s7:45:respawn:/sbin/uugetty ttyS22 38400 vt100
#s8:45:respawn:/sbin/uugetty ttyS23 38400 vt100


Make sure that you have the corresponding entries in the /etc/gettydefs file. Also don't forget to make new uugetty configuration files in the /etc/default directory.

4. At boot up the kernel will not report the new tty's. 

The serial ports are configured when the rc.serial script is run. You can see that on the screen during boot up.

ps ax should show the uugetty connected. Here is part of my ps output.

18208 ? S 0:00 /sbin/uugetty ttyS18 38400 vt100
18247 ? S 0:00 /sbin/uugetty ttyS20 57600 vt100
18254 ? S 0:00 /sbin/uugetty ttyS19 38400 vt100
18258 ? S 0:00 /sbin/uugetty ttyS17 38400 vt100
18260 ? S 0:00 /sbin/uugetty ttyS16 38400 vt100

Finally test the board by dialing out (using cuaXX) and then dialing in (ttySXX).

Good Luck!