UNIX for Dummies Questions & Answers

hi. Im trying to install a switch.
And the manual says i should type a command including a SerialPortDevicePath. which is the filepath to serial port used for connection.

However.. nothing about how to find this info.
Could anyone help me where to find this path?

thx
mr.T

Hi,

It depends on the OS you're using... it is something like /dev/cua0...

Oh. im in mac OSX

no cua0 files in my /dev directorey.
lots of others though. any idea?

Do an ls /dev/cua*, I think it will be called cuaa or something on BSD.

I thought that the /dev/cua* convention had been deprecated in favour of /dev/ttyS* - or is this a Linux only thing?

Cheers
ZB

I though /dev/cu* was the convention with Darwin, although I am not completely sure on this.

Most systems will have both a cua* and a tty* device. The major number will be the same. The minor number will be a little different. One is for calling out. The other is for receiving a call.

When a program like getty tries to open the port, it must block and wait until the modem answers a call. After the modem established a link with the remote modem, it will raise DCD (data carrier detect). At this point the open system call will finally succeed and the getty will display a prompt. This will be using a tty* style special file.

But a program like tip or cu can't wait for DCD. The open must succeed immediately. Then the program will send atdt5551212 or whatever to the modem to start a call. These programs need to use a cua* style device.