It's almost definitely just another way of connecting to the same circuit. If it's a silly voltage it'll fry it whether connected via shoe, PC cord or a bit of wet string. The only way to protect it would be to use a Safe-Sync device, or with a radio or optical trigger.
That said, the international standard for trigger voltages says that modern cameras have to be able to cope with 24V, which most can. If it's got a PC connection it's less likely to be a wimpy Canon (Canons are rated to a pathetic 6V) so you might be ok...