ETS 2604
CyberResearch
®
Serial Communications
6
©Copyright
2008
CyberResearch, Inc.
Configuration
Before you can access a serial port, you must “install” it to the client computer. Launch the “SeaLink
Configuration” console utility by typing “/usr/sbin/sealinkcfg”. If your device is on the local network, you should
see it listed. Type ‘i’ followed by the number of the hub in the list (probably “i 1”) to install it. If your device is not
listed, type 'n' and follow the prompts to tell the software about your device.
You must also configure the RS mode before use if your device supports multiple electrical interfaces. To do this,
open the “SeaLink Configuration” utility by typing “/usr/sbin/sealinkcfg” and set each port’s mode using the ‘p’
command. Be sure to configure the hardware to match the desired setting (see section Electrical Interface Selection).
Warning: Be careful when setting the RS mode, because the mode may conflict with the one set in the Web
Configuration page. If the two conflict and the “Always use defaults” checkbox is not checked, the mode may be set
incorrectly for a brief period or, worse, just set incorrectly. To be safe, leave the Web Configuration page’s RS
mode set to “No Default”.
When finished configuring ports, type ‘q’ to quit. The SeaLink driver must be restarted (or started for the first time),
so type either “/sbin/sealink restart” or “/sbin/sealink start”. If one gives you an error, try the other one.
Usage Details
Once a device has been installed, it can be accessed through the character devices “/dev/ttySL[0-n]”, where ‘n’ is
the number of ports on your device – 1. For example, “echo hello > /dev/ttySL0” will send the ASCII characters
“hello” to the first serial port on your device, while “echo hello > /dev/ttySL2” will do the same for the third serial
port. Additional installed ports will be assigned to the next available range, so if you have two four-port devices
installed they will be assigned to “/dev/ttySL[0-3]” and “/dev/ttySL[4-7]” respectively.
The /dev/ttySL devices are designed to virtualize a serial port, so programs can access them just like a /dev/ttyS port
using the termios functions (see the man page for termios). Note that unlike a normal serial port, SeaLink serial
ports can only be opened by one program at a time. This is done to ensure that the correct client receives the correct
data/signals.
