AN EMB140 CAPT RPTS MAINT ATTEMPTING TO DEFER THE CAPT'S PUSH TO TALK BUTTON. THE REAL PROB WAS THE FLT DECK INTERPHONE BTWN CAPT AND FO AND BTWN FLT CREW AND CABIN WAS INOP.

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DURING OUR FLT FROM ZZZ1 TO ZZZ; I NOTICED THAT THE INTERPHONE COMS BTWN THE CAPT SIDE AND THE FO AND FLT ATTENDANT WAS INTERMITTENT. WHEN WE WERE APCHING AT ZZZ IT GOT WORSE UP TO THE POINT THAT I LOST THE INTERPHONE SYS ON MY SIDE. IT WAS IMPOSSIBLE TO COMMUNICATE WITH THE FO AND FLT ATTENDANT. WE NOTICED THAT THE 3 POS PUSH TO TALK SWITCH ON MY YOKE WAS CREATING ALL THE PROBS WHEN IT WAS IN THE 'HOT MIKE' POS. AFTER WE LANDED AT ZZZ I RPTED THE PROB TO MAINT ALSO WAITED FOR THE TECHNICIAN TO PERSONALLY EXPLAIN THE PROB. WE HAD 3 HRS SITTING TIME. SO THE PROB CAN BE FIXED FOR OUR NEXT FLT. AN HR BEFORE DEP TIME I WENT TO THE ACFT; I NOTICED THAT THEY PUT THE PUSH TO TALK BUTTON ON MEL (MEL #23-22) BUT MY INTERPHONE SYS WAS STILL NOT WORKING. I WAS UNABLE TO COMMUNICATE WITH THE FO AND FLT ATTENDANT. THE PUSH TO TALK SWITCH WAS WORKING; THE PROB WAS THE INTERPHONE FUNCTION. I WENT THROUGH THE MEL BOOK AND I NOTICED THAT THE ONLY APPLICABLE MEL WAS MEL #23-10 AND IT REFERS TO THE INTERPHONE FUNCTION BTWN COCKPIT AND CABIN AND ALSO STATED THAT IS ALWAYS REQUIRED SO MEL #23-22 WAS NOT APPLICABLE. I CALLED MAINT AT ZZZ AND THEY AGREED WITH ME. FOR SOME REASON MAINT CTL DID NOT AGREE BUT EVERYTHING WAS IN BLACK AND WHITE ON THE MEL BOOK.