[c-ubr] VOIP line always on on UBR924

[Michel Py]

I'm having a minor issue with UBR924s: Everything works fine but when
hooking an analog phone that has line activity detection, the line
appears to be on all the time (the led on the phone is always on).

I have tried everything I could under config-voiceport to no avail. It's
not specific to my hardware (does it on several boxes). Any ideas,
anyone?

Thanks
Michel.

Barebones config between two of them:

interface Ethernet0
 description internal network
 ip address 192.168.2.2 255.255.255.0
 no ip mroute-cache
 no cdp enable
!
interface cable-modem0
 description not in use
 shutdown
 no cable-modem compliant bridge
 cable-modem voip clock-internal
!
voice-port 0
 input gain -2
 output attenuation 0
!
dial-peer voice 1000 pots
 destination-pattern 1000
 port 0
!
dial-peer voice 1100 voip
 destination-pattern 11..
 session target ipv4:192.168.2.3

ubr924#sh voice port 0
Foreign Exchange Station 0 Slot is -1, Port is 0
 Type of VoicePort is FXS
 Operation State is DORMANT
 Administrative State is UP
 No Interface Down Failure
 Description is not set
 Noise Regeneration is enabled
 Non Linear Processing is enabled
 Music On Hold Threshold is Set to -38 dBm
 In Gain is Set to -2 dB
 Out Attenuation is Set to 0 dB
 Echo Cancellation is enabled
 Echo Cancellation NLP mute is disabled
 Echo Cancellation NLP threshold is -21 dB
 Echo Cancel Coverage is set to 8 ms
 Playout-delay Mode is set to default
 Playout-delay Nominal is set to 60 ms
 Playout-delay Maximum is set to 200 ms
 Playout-delay Minimum mode is set to default, value 40 ms
 Connection Mode is normal
 Connection Number is not set
 Initial Time Out is set to 10 s
 Interdigit Time Out is set to 10 s
 Ringing Time Out is set to 180 s
 Companding Type is u-law
 Region Tone is set for US

 Analog Info Follows:
 Currently processing unknown
 Maintenance Mode Set to None (not in mtc mode)
 Number of signaling protocol errors are 0
 Impedance is set to 600r Ohm
 Wait Release Time Out is 30 s
 Station name michel, Station number None

 Voice card specific Info Follows:
 Signal Type is loopStart
 Ring Frequency is 25 Hz
 Hook Status is On Hook
 Ring Active Status is inactive
 Ring Ground Status is inactive
 Tip Ground Status is inactive
 Digit Duration Timing is set to 100 ms
 InterDigit Duration Timing is set to 100 ms
 No disconnect acknowledge
 Ring Cadence is defined by CPTone Selection
 Ring Cadence are [20 40] * 100 msec