intercom bpt yc/200 handset replace

[Isaachierro]

hello, i have a faulty bpt yc/200 faulty handset, i just moved to a building and i figured out my intercom is not working propertly, when someone buzz my aparment number my handset doesnt buzz at all (im newbie but i must tell i didnt see any speaker inside my intercom handset, ill add you some pics below), when i pick up the handset i can hear the people talking outside and i can buzz people in but they cant hear me (i dont know if the mic is not working or something like that). i would like to know if i can just buy a new intercom handset and replace this old one and how should i connect the new one or if theres a new to make my old one work again. please look at my pics and help me out with this.

 

[Handymanjo]

If can hear people at the entrance station and also open door from handset seams to be ok.
It would look at the call button on the entrance station.if it is not buzzing handset button could be faulty.
Open entrance station and short across button,if handset buzzers then faulty call button.

 

[Isaachierro]

its seems to be ok but i will give it a ty and let you know, what about people not hearing me? what can i do to solve that? is there a kind of universal handset i can use to replace this old one?

 

[sparkymarka]

Agata C200 is the replacement handset for the YC200 , the single red wire is the buzzer wire , how many flats in your block ? Do other people have issues with the outwards speech ?