Connection between two phones

Let me tell you how to solve your problem in a way you can best understand. :) yikes..

Your handset has lost the ability to communicate with your base. If you have had storms in your area, or you had a static discharge on the handset (it is winter), it could make this happen, sometimes terminally (needs repair or replacement). However, You need to attempt to re-register your handset to the base station, its fairly easy to do. You will have to put your handset and base into "registration mode" simultaneously. Grab your fully charged handset and stand your base station. On your cordless handset push menu, scroll down to base settings, push ok, scroll down to base station 2, then press ok, scroll down to register and push ok, enter your base pin, or 0000 and push ok. Handset should be flashing "registering base station 2". Now quickly, On your base station push menu,scroll forward to system settings, push select, enter your pin or 0000 then push select. Push select again for Handset Registration, the screen should be flashing Handset registering or something to that effect ( I am at home ). So now your base and handset are "searching" for each other to register. Watch your handset, and if it sees the base, the display will flash and ask you to assign the intercom number, just push OK. If that doesn't work, I can help you more. Just let me know.

There might be two problem....1st of programming and 2nd one of internal hardware problem of your handset which is not working.

For the 1st option- Read manual carefully, there is security setting. Follow the steps with second one handset which is not responding.( I can assum that it is power on but not responding to signals..May i right?) After completing security process it will give long beep and will bond with other one and that is necessary for frequiency adjustment. This generally occures after removal of batteries.

For the 2nd option- There is crystal inside your handset which is resposible for generat stable and similar frequency as other handset. When that crystal lost its capacity it results in mismatching of frequency and occures in non connection results in no response from handset. This can be repaired by technician after getting part no of that crytal from your device and replace it with another one. But for this you have to visit technician with all of handsets and attachment as it is necessary to check it working properly after repair, even technician may also need it for setting frequency level.
Is it clears all doubt about this problem then say FIXYA......