Let me begin with my apologies for again starting a new thread on this same topic. I am still not receiving the email notifications for postings so I am unable to Reply to them and thereby keep the thread contiguous. ================================= I tried having my SIP line vendor change the port to 5080 and that initially helped, but did not, by itself, fully establish the connection. I then made changes to the following configuration xml files conf\vars.xml I changed the default Password I defined the external_sip_ip & external_rtp_ip to be those of my SIP vendor conf/dialplan\public\00_inbound_did.xml I added in a new 'extension' which reflected the phone number of the 'caller' and defined the Action to take With these changes things started working (albeit in a simplistic manner) Then, in order to minimize the variables, I had my SIP line vendor return to its original port 5060 Things continued to work as before. So the 'outside' line port did not seem to make any significant difference. I will likely start a new thread about how to install in-house SIP phones onto the FreeSWITCH system (which xml files to modify, etc.) if I cannot make the correct guesses on my own. ( I hope that the list admin can 'knit' these various threads back into a single consolidated thread ) Thank you for your advice/assistance.