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Mario Manzano

Calls get dropped (busy signal) at FXS port... nowhere to go?

Hello evereyone!

Thanks in advanced for looking.

We have a CISCO 2901 router configured with DMVPN and IP CISCO phones 7945 that is part of our WAN. We have 4 digit calling across the VoiceNetwork on 3 different states (using Call Manager)

We recently added another office with the equipment described above. They get POT (Plain Old Telephopne) lines to the office, which are connected to the router into the FXS port (0 and 1).

When they dial 9 from any 7945 phone, it does not find a line; they get the attendant's voice "Sorry, your call could not be completed as dialed"

If someone calls any given line, you can see the FSX corresponding port light up and then a busy signal.

I am attaching the router's config. I did NOT configure the router as I don't have enought expertise to do so like that.

I am guessing that there is either a translation pattern missing, an OFF setting or something of that nature.

Thank you for your help!

Tagir Temirgaliyev
Frequent Contributor

put here

show inven

show ver

where is telephone whith number 1200 ?

any call from pots goes to number 1200 but no dial-peer to that   dial-peer to 1200 ok.

is voice ports FXS or FXO ?

you need also to check CUCM configuration

Thanks for replying!

number 1200 is an extension... goes to 4 phones at the same time. Configured in Call Manager.

Voice ports are FSX

I am going through CUCM config as well...

POA2901#show inven
NAME: "CISCO2901/K9", DESCR: "CISCO2901/K9 chassis, Hw Serial#: FTX1727Y01Q, Hw Revision: 1.0"
PID: CISCO2901/K9      , VID: V06 , SN: FTX1727Y01Q

NAME: "2nd generation four port FXO voice interface daughtercard on Slot 0 SubSlot 2", DESCR: "2nd generation four port FXO voice interface daughtercard"
PID: VIC2-4FXO         , VID: V04 , SN: FOC17316LUN

NAME: "PVDM3 DSP DIMM with 16 Channels on Slot 0 SubSlot 4", DESCR: "PVDM3 DSP DIMM with 16 Channels"
PID: PVDM3-16          , VID: V01 , SN: FOC17244F1B

NAME: "C1941/C2901 AC Power Supply", DESCR: "C1941/C2901 AC Power Supply"
PID: PWR-1941-2901-AC  , VID:    , SN:

POA2901#show ver
Cisco IOS Software, C2900 Software (C2900-UNIVERSALK9-M), Version 15.2(4)M3, RELEASE SOFTWARE (fc2)
Technical Support:
Copyright (c) 1986-2013 by Cisco Systems, Inc.
Compiled Tue 26-Feb-13 03:42 by prod_rel_team

ROM: System Bootstrap, Version 15.0(1r)M16, RELEASE SOFTWARE (fc1)

POA2901 uptime is 22 hours, 43 minutes
System returned to ROM by power-on
System restarted at 13:05:57 CDT Thu Oct 3 2013
System image file is "flash0:c2900-universalk9-mz.SPA.152-4.M3.bin"
Last reload type: Normal Reload
Last reload reason: power-on

This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
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to comply with U.S. and local laws, return this product immediately.

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Cisco CISCO2901/K9 (revision 1.0) with 909312K/40960K bytes of memory.
Processor board ID FTX1727Y01Q
2 Gigabit Ethernet interfaces
1 terminal line
1 Virtual Private Network (VPN) Module
4 Voice FXO interfaces
DRAM configuration is 64 bits wide with parity enabled.
255K bytes of non-volatile configuration memory.
250880K bytes of ATA System CompactFlash 0 (Read/Write)

License Info:

License UDI:

Device#   PID                   SN
*0        CISCO2901/K9          FTX1727Y01Q

Technology Package License Information for Module:'c2900'

Technology    Technology-package           Technology-package
              Current       Type           Next reboot
ipbase        ipbasek9      Permanent      ipbasek9
security      securityk9    Permanent      securityk9
uc            uck9          Permanent      uck9
data          None          None           None

Configuration register is 0x2102

Hi Mario,

you need to add the gateway as a sip trunk in the call manager.

or try to add this gateway as h323 in the call manager.



please rate all helpful posts

THANKS! ... It is the only office with different config... Adding SIP trunk now..

router config looks like ok.

can extentions call each other? can extentions call number 1200 ?

check call manager side. is there sip trunk pointed to router ip address ? and which?

can you ping call manager servers and ?

Yes, ext can call eachother... Yes we can all call 1200...

Yes, can ping 120.11 & 12

Nope... no SIP TRUNK... working on it now.

Never done this before so it might take me a while...

Mario Manzano

update on issuie.... RESOLVED!

There is a sort of bug / feature

Compressed audio on CCM is by default g729br8 and Compressed Audio on CME/SRST/CUBE is g729r8 by default.  We can turn on br8 on the gateway voice class codec, but doing so causes the transcoders and conferencing resources to be in high complexity mode and thus process less calls.

There is a setting now on CCM to disable br8 and there is a setting on the gateway to have it use br8 instead of r8.  In this case the setting was missing from the config.

turned it on, and calls are now working properly.

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