If you are going to be working with network gear you will definitely want a serial port, it is the only guaranteed way to access a device console regardless of it's state or config. Take ewwhite's advice and get yourself an USB-to-serial adapter.
You mentioned that the switch is hooked up to a router, if they are physically near each other you can use the following nifty trick to access the console port in a pinch:
You need a cisco console cable with RJ45 connectors on both ends. You will use that to connect the CON port of the device you want to login to (device A) with the AUX port of a device we you have access to (device B, e.g. the router).
Login to device B and configure it’s AUX port with these settings:
# conf t
# line aux 0
(config-line)# modem InOut
(config-line)# transport preferred all
(config-line)# transport input all
(config-line)# transport output all
(config-line)# stopbits 1
(config-line)# end
Device B has to have a loopback address and it must be up. Now we have to find out which port we are going to have to telnet to. Do a show line
from the enable mode, the output should look something like this:
Tty Typ Tx/Rx A Modem
0 CTY – –
* 97 AUX 9600/9600 – inout
* 98 VTY – -
Our line is number 97
, telnet to the loopback address and port 2000+our line. If our loopback had the IP 192.168.100.200
the command would be telnet 192.168.100.200 2097
in this example.
I've used this trick a few times in the past when I had to remotely access the CON port of a device when the person on-site didn't have the right cable or laptop.