Panasonic PBX KX-T61610B Problem

[Guest]

Dear All Experts
I got the problems with Panasonic KX-T61610B PBX system.
My key phone Model number is KX-T7030X.When I connect to Ext.11 to 18 with this key phone,I can do only out going calls with head set,speaker phone doesn't work with these extensions.
When I install my key phone to one extension from (11 to 1.I can only outgoing calls.When I call to key phone install extension with other phone,I can hear calling tones,but the keyphone extension doesn't ring tone.
When I install the key phone to Ext 19 to 26,the LCD displays "Program Mode",at that time my PBX and key phone are not set in "Program" switch.
So I can't make any programing for my PBX anymore.
I've already change the battery (CR2354).It still doesn't work.
What should I do for my problem.
Pls suggest my problem.
Thanks in advance.

Best Regards
Wilson