hello I want to create a telephone board for using in elevator work with two voltage +12 and +24 volt.
and connected two wire from communication

 

Before any design concepts can be created we need a more detailed description of what
"Build an Emergency Telephone PCB for Elevator "
means to the Thread Starter! An Emergency phone system could consist of two handsets, wire, and a single battery. OR a load of MSA-Certified emergency phone packages. About $10,000 difference. At least.

 

We need a LOT more information.

How tall is the elevator?
Is the elevator already wired for telephone communication?
Does the telephone interface with an external phone system, or only a security desk?

ak

 

In addition to the good points made in post #3, there are a bunch of rules about everything associated with elevators, and a lot more than those if the elevator can be accessed by the general public.

 

hello I want to create a telephone board for using in elevator

Where are you located?

ak

 

What are the +12 V and +24 V sources? Is +24 V intended for the telephone circuit? Is +12 V for a separate microphone/speaker circuit?

 

The simplest? A wireless link.

 

The simplest? A wireless link.

There is nothing at all simple about a wireless link. AND they are seldom "private" links. Each end of the wireless link must have both a transmitter and a receiver, both having power source requirements.

 

If it is for emergency calls only, it could be straightforward without need for much privacy.
But we would have to know the exact requirements, which the TS hasn’t yet provided.