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Enabling E&M control signals pass-through
This feature operates only when the E&M non-signaling mode is enabled. As shown in Figure 6, an E&M
virtual private line is set up between the tone generator and the radio. Enable E&M control signals
pass-through for Router A and Router B so that they can send seize and idle signals for the E&M virtual
line over the IP network.
Figure 6 E&M analog control signals pass-through
To enable E&M control signals pass-through:
Step Command Remarks
1. Enter system view.
system-view
N/A
2. Enter voice interface view.
subscriber-line line-number N/A
3. Enable E&M control signals
pass-through.
passthrough
By default, this function is disabled.
Configure this command on both
the originating and terminating
devices.
Configuring the output gain of SLIC chip
Step Command Remarks
1. Enter system view.
system-view N/A
2. Enter voice interface view.
subscriber-line line-number N/A
3. Configure the output gain of
the SLIC chip.
slic-gain { 0 | 1 }
Optional.
The default is 0 (0.8 dB).
This command controls signal
amplification.
Configuring DTMF
Dual tone multi-frequency (DTMF) uses a mixture of a high frequency tone and a lower frequency tone to
represent a key on a keypad. Each column of keys is represented by a high frequency tone and each row
of keys is represented by a low frequency tone. For example, as shown in Figure 7, the di
git 1 is
represented by the combination of a pure 697 Hz signal and a pure 1209 Hz signal. Such DTMF tones
have good immunity to interference.
