VG224 integration with overhead paging via CallManager

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Jan 10th, 2008
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Using VG224 FXS port to integrate overhead paging. VG224 is registered with CallManager, but continous off-hook dial tone is presented on overhead speakers. Is this a config issue or is additional hardware required.

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christopher.l.l... Fri, 01/11/2008 - 10:45
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I think we need some more details on your overhead paging system and what it requires. It may just be a jumper setting on the paging system for the line type.

On the VG224, make sure you have the latest firmware as the early versions had some quirks and the later versions have a few extra options. On the port setting, set call control mode to restricted to avoid accidentally triggering stuff like hold and forwarding. Set the MWI method to none as the lamp voltage may trigger the paging system to go or stay offhook. You may need to change the call supervision method to "drop loop current" or "reverse polarity" to get the paging system to hang up at the end of the call (I suspect this is your problem, btw). Fri, 01/11/2008 - 11:14
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Where are the parameter changes for the "drop loop current" and "reverse polarity" on the VG224. the IOS is latest 12.4(11)T.


christopher.l.l... Fri, 01/11/2008 - 11:38
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I'm guessing your using Call Manager Express since you mention IOS. The changes are on the unit itself rather than in CM or the router running CME. I'm looking at my VG248 right now, which is the 48-port version of the VG224. If you telnet into the unit, go to configure->telephony->port specific parameters,arrow down to the port and hit return. Fri, 01/11/2008 - 13:31
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I meant the IOS of the VG224, it was a new unit with a 12.4(2) image, so I upgraded to 12.4(11)T. we are using Call Manager 4.2(3). Where do you find the parameters to change the loop current as you suggested and the polarity reversal We are using the VG224 to interface the Bogen-TPU amplifiers on the overhead paging.


christopher.l.l... Fri, 01/11/2008 - 14:43
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I did not realize the VG224 ran IOS. I thought it was the 24-port version of the VG248 which does not run IOS. Here is the software config guide for the VG224 I believe you have some options in Call Manager for port type such as ground-start and loop-start that you might try changing.

I'm not sure what options you have within the web interface. At the IOS command line, you can enter config mode, go to the voice-port x/x and look at the available options by hitting "?". Looking at another IOS based gateway I see options for "battery-reversal" and "mwi".

c.yeo Mon, 01/21/2008 - 09:10
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RE: port setting

I have run into this, but I can't find the 'call-control' setting(s) you are talking about. I checked the voice-port and the CCM (4.3.2) pages with no luck.


jroysdon Tue, 01/15/2008 - 09:19
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Sounds like your paging system needs to hang up and wait for a ring. You may need a device between your paging system and the VG224 that can detect a ring and connect the VG224 to the paging system after it detects this, and then after so many seconds of silence disconnect from the paging system and hang up the VG224 port. The Valcom V-9970 is one such device that I've used in the past to accomplish this where the customer's overhead paging had no intelligence (it just amplified the audio and drove the speakers). I have used this device when connected to an ATA186, which is essentially the same thing your VG224 FXS is providing. Mon, 01/21/2008 - 09:35
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I ended up using the Valcom V-9970 for the overhead paging as in your suggestion, and a V-9924C for the night bell. Seems to work well and install was easy. The confusion was that Cisco PDIO told me that no other device was needed between the VG224 and the amplifier. And I think that they were referring to a VG248.

mightyking Thu, 10/21/2010 - 22:39
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I am configuring a Valcom paging system with my VG224. Could you please share your VG and Valcom config with me?



Steven Holl Mon, 10/25/2010 - 08:17
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Chiming in late, butjust to clarify this: it sounds like the paging system isn't acting as an FXO device (which is what it needs to to be connected to an FXS).  Hence, the loop is always closed on the paging system, which makes the FXS port think the device is always offhook (so it plays dialtone to it).

This is typical of paging systems which are essentially just a PA amplifier (line audio input) and provide no call control.  Typically those would be integrated via an E&M port, instead of an FXS.  (Unless you use an external FXO device to convert to an E&M or standard tip/ring audio connection on the other side). Mon, 06/13/2011 - 00:13
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I have the same issue with a vg224 connected to a valcom 9940 the ip phone hangs up but the paging system goes to dail tone and then busy. did you find something on the port or dial peer to disable this?

paolo bevilacqua Mon, 06/13/2011 - 02:28
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    Founding Member wrote:

I have the same issue with a vg224 connected to a valcom 9940 the ip phone hangs up but the paging system goes to dail tone and then busy. did you find something on the port or dial peer to disable this?

You have posted this same quesion in another thread already, please avoid posting duplicates.


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