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SPA 3102 and CPC assistance

gshepard
Level 1
Level 1

Hi,

When using a Linksys SPA 3102 in conjunction with a PBX, we are having some trouble with the SPA generating CPC and need assistance in configuring it.

When the caller is on the SIP/IP side and the callee is on the FXS/PBX side:

   caller hangs up, the CPC is generated, the PBX disconnects the line, the caller is disconnected.

   callee hangs up, the SIP/IP side is shut down (BYE), the caller is disconnected.

When the caller is on the FXS/PBX side and the callee is on the IP/SIP side:

   caller hangs up, the SIP/IP side is shut down, callee is disconnected.

   All of the previous scenarios work as expected, except for:

   callee hangs up, the SIP/IP side is shut down, caller (PBX/FXS) port stays off hook and reorder is played to the PBX.  We never see a CPC generated here.

How do we get the SPA to generate CPC in the last case?

Thanks for any assistance you can provide!

1 Accepted Solution

Accepted Solutions

Gabe Shepard

My SPA3102 is running the latest firmware .. 5.2.13(GW002).  When I enable CPC on the SPA3102 Regional Tab by setting a "CPC Duration" there is definitely a change when you use the handset attached to the SPA3102 to call an ip number and the ip number disconnects first.  You hear a silence and then you hear dialtone (not a reorder). When you attach a PBX to the FXS port it is similiar to an analog handset. 

If the CPC Duration is disabled (set to zero) and the callee disconnects you will hear a reorder tone.  I also tried this on a SPA1001 and it did not work the same as the SPA3102 even though it has the same Regional Tab settings.  With the SPA1001 in both cases you heard a reorder tone after the distant disconnect.  The SPA1001 is older so maybe there was a change somewhere along the way.

I do not know how to use a voltmeter to determine if there is an actual voltage drop on the SPA3102 FXS port.  In an attempt to try to determine if the SPA3102 FXS port was sending a CPC signal I attached a SPA3000 FXO port to the SPA3102 FSX port and I dialed an ip number on the SPA3000 into the SPA3102 FXS port to call a distant phone. When the distant phone disconnected I looked at the INFO Tab of the SPA3000 FXO port and it said it received a CPC signal from the SPA3102 as a reason for the last disconnect.

This Cisco FAQ also seems to indicate that the SPA3102 will issue the CPC.

http://www.cisco.com/en/US/products/ps10030/products_qanda_item09186a0080a3655b.shtml#qa17

View solution in original post

7 Replies 7

On the SPA3102 Regional Tab you can specify a CPC Duration (default is 0) for the FXS port.

From the Administration Guide Cisco Small Business

SPA2102, SPA3102, SPA8000, SPA8800, PAP2T,

WRP400:

Duration in seconds for which the tip-to-ring voltage is

removed after the caller hangs up. After that, tip-to-ring

voltage is restored and dial tone applies if the attached

equipment is still off-hook. CPC is disabled if this value is

set to 0. Range: 0 to 1.000 second. Resolution is 0.001

second.

The default is 0 (CPC disabled).

   Thanks for your response.

   We've configured those settings, and CPC is working in one direction, but not the other.   If the caller is on the PBX/FXS side and the callee hangs up, the line is never dropped.

The CPC Duration setting needs to be in seconds, not milliseconds, i.e. for a 500 ms CPC you would have 0.500.

I tried a test call with following setting on the SPA3102 Regional Tab:

CPC Duration: 0.800

I don't have any way to test it with a PBX attached, but when I try the setting on a test call from an analog phone attached to the FXS port and the ip callee disconnects I believe the phone receives an 800 ms CPC signal from the SPA and then since the phone is still off hook the SPA3102 returns dial tone to the phone.

We're currently using a 1 second CPC duration. When testing with a phone, we do hear a brief noise, but have confirmed with a voltmeter that the current is not disconnected. This only seems to happen if the caller is on the PBX side and the callee is on the PSTN, and the callee hangs up.  What version of firmware are you using?  Maybe there's a difference there somewhere?

I think I have some bad news... The term CPC pretty much meant "called party control" in the world of legacy telephony. I've heard it as calling party control also, but how the SPA 3102 seems to be reacting is how it works on POTS lines from Ma Bell, also.

I've got some lines sourced from a NT DMS-100, and they do not provide CPC on an outgoing call. Basically, after the called party hangs up, you get dial tone after about 10 seconds, followed by reorder, followed by "If you'd like to make a call...", followed by Howler. Incoming calls, caller hangs up, 5 seconds go by, 750 ms CPC, followed by dialtone, etc as above.

I have tried this on a SPA2102, SPA122, PAP2T, and a couple of Grandstream ATAs, and they act the same.

Like you said above, it's described as:

"CPC Duration: Duration in seconds for which the tip-to-ring voltage is

removed after the caller hangs up. After that, tip-to-ring

voltage is restored and dial tone applies if the attached

equipment is still off-hook."

On an outbound call, it's the called party hanging up, not the caller. If it truly was the caller hanging up (your pbx) then, problem solved. This was a big problem on PBXs and key systems with loop start lines that had people that might want to beat the restrictions. Call home, have them hang up, and dial the world on the new dial tone.

If you've gotta have it on outbound, you might have to put one of these inline.

http://www.vikingtelecomsolutions.com/catalog/model_CPC-1.htm

Gabe Shepard

My SPA3102 is running the latest firmware .. 5.2.13(GW002).  When I enable CPC on the SPA3102 Regional Tab by setting a "CPC Duration" there is definitely a change when you use the handset attached to the SPA3102 to call an ip number and the ip number disconnects first.  You hear a silence and then you hear dialtone (not a reorder). When you attach a PBX to the FXS port it is similiar to an analog handset. 

If the CPC Duration is disabled (set to zero) and the callee disconnects you will hear a reorder tone.  I also tried this on a SPA1001 and it did not work the same as the SPA3102 even though it has the same Regional Tab settings.  With the SPA1001 in both cases you heard a reorder tone after the distant disconnect.  The SPA1001 is older so maybe there was a change somewhere along the way.

I do not know how to use a voltmeter to determine if there is an actual voltage drop on the SPA3102 FXS port.  In an attempt to try to determine if the SPA3102 FXS port was sending a CPC signal I attached a SPA3000 FXO port to the SPA3102 FSX port and I dialed an ip number on the SPA3000 into the SPA3102 FXS port to call a distant phone. When the distant phone disconnected I looked at the INFO Tab of the SPA3000 FXO port and it said it received a CPC signal from the SPA3102 as a reason for the last disconnect.

This Cisco FAQ also seems to indicate that the SPA3102 will issue the CPC.

http://www.cisco.com/en/US/products/ps10030/products_qanda_item09186a0080a3655b.shtml#qa17

Thanks for the help, everyone.  It does look like this was a firmware issue -- we upgraded to the latest 5.2.13 and it's working correctly in every scenario we've tried.  There's a note in the release notes as well:

"Fixed an issue in which the line was not disconnected properly after the remote end disconnected. (CSCtl92028)"

that may refer to this problem, so if anyone else happens to run into it, check the firmware sooner, rather than later!

-Gabe

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