Multicast RTP is one way only from the sender to the multicast address(es) (receiver). For
outgoing RTP multicasts, all other existing calls on the phone will be placed on hold.
Sending RTP Stream via a Paging List Key
To send RTP stream via a paging key list when the receiver’s phone is idle:
1. Press the paging list key when the phone is idle.
2. Select the desired group.
3. Press the Paging soft key to send RTP.
4. To place the current multicast RTP session on hold, press the Hold soft key.
The sender’s phone places the multicast RTP session on hold and receiver’s phone releases
the session.
5. To resume the held multicast RTP session, press the Resume soft key.
The multicast RTP session is established again.
6. To end the multicast RTP session, press the multicast paging key again or press the EndCall
soft key.
DTMF
DTMF is the signal sent from the IP phone to the network, which is generated when pressing the
IP phone’s keypad during a call. Each key pressed on the IP phone generates one sinusoidal
tone of two frequencies. One is generated from a high-frequency group and the other from a
low-frequency group.
DTMF Keypad
The DTMF keypad is laid out in a 4×4 matrix, with each row representing a low-frequency, and
each column representing a high frequency. Pressing a digit key (such as '1') will generate a
sinusoidal tone for each of two frequencies (697 and 1209 hertz (Hz)).
DTMF Keypad Frequencies: