Of Macs and serial ports

My trusty iBook, as all Macintosh computers manufactured in the last few years, have no serial port. That has never stopped me from doing work as I had a Linux laptop, a Dell Latitude D600, which I would bring whenever I needed to talk to a Cisco switch or use as console for a Unix workstation (say, Sun Solaris or IBM AIX box).

But, then, the Dell laptop died. And I needed to configure a cisco switch from scratch... at least configure it enough so I could then telnet to it. To do that I needed to connect the famous Cisco blue console cable to the Mac. I needed a usb-to-serial cable.

Not knowing where to find one of those usb-to-serial cables, I decided to try one of my favorite places: geeks.com. I not only found it but here is a picture of the cable:

Clicking on the image *should* lead you to the link for the cable. After I received it, I connected it to the Mac. The laptop was aware of the device, even recognizing its chipset. But, it would not be available for use. Here is what I mean:

Mireille:~ dalek$ ls /dev/tty.*
/dev/tty.Bluetooth-Modem                /dev/tty.Nokia6103-NokiaPCSuite-1
/dev/tty.Bluetooth-PDA-Sync             /dev/tty.modem
/dev/tty.Nokia6103-Dial-upnetwor-2
Mireille:~ dalek$ 

Clearly, I need a driver for it. Examining the information shown by the machine about the driver, we see the chipset is made by prolific. After a bit of searching online, I found the manufacturer's site and downloaded the drivers from its site. Do note in that page that they also have drivers for Windows and even Linux. I do not know if Linux would ever need such a driver; finding that out is for a different episode. Anyway, after installing it, we had to reboot the laptop. After that, it was time to connect the usb-to-serial cable and find out if it was seen as a device we could use. Can you spot the new entry?

Mireille:~ dalek$ ls /dev/tty.*
/dev/tty.Bluetooth-Modem                /dev/tty.Nokia6103-NokiaPCSuite-1
/dev/tty.Bluetooth-PDA-Sync             /dev/tty.modem
/dev/tty.Nokia6103-Dial-upnetwor-2      /dev/tty.usbserial
Mireille:~ dalek$ 

Now we have a device, tty.usbserial, we can try it out. We could install minicom using fink, but we can be a bit lazy and use, of all things, screen. Believe it or not, screen can also be used to connect to a terminal device. So, if you type something like

Mireille:~ dalek$ screen /dev/tty.usbserial 9600

you would be telling screen to connect to our usb-to-serial cable, identified as tty.usbserial, at 9600baud which happens to be the default port speed for a Cisco switch. Neat, huh?