[Telephone in use indicator]

thanx friends!i see what i want,telephone line monitor&phone line indicator,but this i get a problem in language can some one translate in english pls!& on telephone line monitor i get a trouble where to connect the base leg of the transistor that in series with the speaker.&if some one could help me to analyse how the mathematical value of the components such as capacitor&resistor were obtained.and also how the circuit electronically works.pls help me im stack.

[Telephone in use indicator]

pls could u help me to design a simle circuit that will help me to detect someone who steel ma phone line,by taps.that circuit will inform with sound or any alert system,or give information to the telephone service provider.malick