You should be able to access the router using a web-interface. At this point, there should be information about what port(s) are being used.
Like Technochic said, please try to be more specific.
Ports can be in hexadecimal. Take for example the output from a show ip cache flow on a Cisco router. The source/destination ports are in hex. You will need a conversion calculator like the one in Windows. To find out the standard services on various ports, check out the list at IANA.