Using FXO POTS line for 911 calls

Unanswered Question
Jul 24th, 2007

I am trying to make use of a POTS line connected to FXO port on 2851 for 911 calls going out of the router. I understand that dial-type, signaling type is important and I have checked that to be dtmf and loopstart respectively. Here is my configuration, but it is not working. The call is not getting out through this port instead using a redundant pri to go out.

voice-port 0/3/0

description POTS line

!loopstart and dtmf are default settings

dial-peer voice 880 pots

!translation-profile outgoing pstn

destination-pattern 911

port 0/3/0

forward-digits all

Can anyone give me some ideas what else I need to check?

I have this problem too.
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ybpants Mon, 08/06/2007 - 15:50

Try making the preference of the dial-peer voice 880 pots so it is a higher preference then the PRI:

dial-peer voice 2911 pots

description *** 911 calls over PRI - Secondary ***

preference 1

destination-pattern 911

port 0/0/0:23

forward-digits 3


dial-peer voice 1911 pots

trunkgroup AnalogTrunks

description *** 911 calls over FXO - Priority 1 ***

preference 0

destination-pattern 911

forward-digits 3


using this method I send all 911 calls over the analog FXO line by default but if for any reason that is unavailable the PRI will be used

The command "trunkgroup AnalogTrunks" is so it will use any 1 of the 4 FXO ports to send the call. The trunk group is configured by adding the command "trunk-group AnalogTrunks" to each of the voice-ports on the FXO card

ranjanibharadwaj Tue, 08/07/2007 - 08:42

Thanks for responding to my issue. I have setup a preference for my dialpeer. The problem is layer 1 I think. I have put a plar on the pots dial-peer. It is interesting that incoming call works just fine. It rings on my IP phone, but the outgoing call fails. 'debug vpm signal' gave the following logs:


Aug 7 12:39:27.048 EST: htsp_process_event: [0/3/0, FXOLS_ONHOOK, E_DSP_SIG_0110]

Aug 7 12:39:27.048 EST: fxols_line_reversal_clid_wait. On_hook line reversal detected possibily due to crossed cable

Aug 7 12:39:27.420 EST: htsp_process_event: [0/3/0, FXOLS_ONHOOK, E_DSP_SIG_0110]

Aug 7 12:39:27.420 EST: fxols_line_reversal_clid_wait. On_hook line reversal detected possibily due to crossed cable


Aug 7 12:39:46.156 EST: htsp_timer_stop3 htsp_setup_req

Aug 7 12:39:46.156 EST: htsp_process_event: [0/3/0, FXOLS_ONHOOK, E_HTSP_SETUP_REQ]fxols_onhook_setup

Aug 7 12:39:46.156 EST: [0/3/0] set signal state = 0xC timestamp = 0

Aug 7 12:39:46.156 EST: htsp_timer - 1300 msec

Aug 7 12:39:46.408 EST: htsp_process_event: [0/3/0, FXOLS_WAIT_DIAL_TONE, E_DSP_SIG_1100]fxols_power_denial_proc

Aug 7 12:39:46.408 EST: htsp_timer2 - 1000 msec

Aug 7 12:39:46.408 EST: htsp_timer_stop

Aug 7 12:39:47.409 EST: htsp_process_event: [0/3/0, FXOLS_WAIT_DIAL_TONE, E_HTSP_EVENT_TIMER2]fxols_timer2_proc

Aug 7 12:39:47.409 EST: htsp_timer_stop

Aug 7 12:39:47.409 EST: htsp_timer_stop2

Aug 7 12:39:47.409 EST: [0/3/0] set signal state = 0x4 timestamp = 0

Aug 7 12:39:47.409 EST: htsp_process_event: [0/3/0, FXOLS_ONHOOK, E_HTSP_RELEASE_REQ]fxols_onhook_release

Any leads on 'On_hook line reversal'?

My dial-peer is as follows:

dial-peer voice 880 pots

preference 1

destination-pattern [2-9]11

port 0/3/0

forward-digits 3

voice-port 0/3/0

signal groundStart

connection plar 3706610

description POTS line - test

Thanks in advance.

shikamarunara Sun, 08/12/2007 - 18:52

I would take an analog phone and plug it into the wire that normally goes to the FXO. If so, qualify whether this is loopstart of groundstart (your debug is expecting loop start but your voice port is configured as ground start.


ranjanibharadwaj Mon, 08/13/2007 - 05:39

We were not able to connect a regular phone (with loopstart) and make a call out, thats when Telco told us that it is ground start.

Any other suggestion?

Thank you in advance.


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