professional telephone designing with low power consuming...

[hm_fa_da]

hi ;


i am designing a public payphone and now i am searching for a good schematic for ONLY audio interface of the phone , it is important that it uses the lowest current and also have a good sound for speaker and enough sensitivity for microphone .( i need only this part not dialler or indicator or .... )

thanks a lot ,
hm_fa_da.

 

[xxargs]

Re: professional telephone designing with low power consumin

hi ;


i am designing a public payphone and now i am searching for a good schematic for ONLY audio interface of the phone , it is important that it uses the lowest current and also have a good sound for speaker and enough sensitivity for microphone .( i need only this part not dialler or indicator or .... )

thanks a lot ,
hm_fa_da.

hmm. you already build line interface???

if selfpowered unit you need take power from PABX-line
- and this give not so much power in worst line situation like
4 mA and 2-4 Volt over line-inteface...

ie only 8-16 mW total power resource...

you like big loudspeaker? - typical 190 Litre exponential
horn speaker can get pretty high sound level on
5 mW power ;-)

---

check how much power you can give to loudspeakers,
and check is power good enough to give wanted
high loud level on selected speaker

if not - increase power resource from extern
power resource or reservoar (line recharge batterie solution)
or select more sensivity speaker...