Dell 2135cn Service Manual page 808

5) When the called party's handset is lifted, activating the hook switch, the local switch on the called
party side receives a response signal and stops sending tones to the calling and called parties.
This is when a communications path is established between the both parties.
Connecting Out-of-Town Calls
a. Lift the handset
Calling party
b. Dial the number
2) Phone number
c. Calling
d. Line established
Hello
Version 1 2008.02.01
Local Tandem
Switch Switch
1) Dial tone
3) Lines are automatically connected.
4) Ring back tone
Communications Path is established.
Chapter 6 Principle of Operation (Fax)
Tandem Local
Switch Switch
Connection established
6 – 9
Called party
4) Ringing
signal
Hello
5) Response
signal
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