ok , so you've put up a catalyst 1900 switch at your home. how many machines have you connected to it ? ( not that it makes any difference to this problem of yours) . You said you are using a cable modem to connect to the internet .... do you plug the modem directly into the switch or do you have a router in between ? As you can ping your internal network , it means the problem is on the outside . First check the port on the switch which you are using to connect to the modem or router.If you can assign an IP to the modem , see if you can ping that . You could even setup a machine bypassing the switch and see if you can access the internet .