I have a monitored system which includes a PC5010 and PC5928 in it. How hard is it to install the DSC5401 or DSCIT-100 in this system. Will I need to get the monitoring company to come out and enable the serial port, or is this something I may do myself from my keypad? I have not been able to find any definitive answers or installation instructions matching what I have. Thanks for any help you can provide.