atcomsystems.ca/forum Forums Other TDM Phone Systems Vertical Telephones & Systems Won't release line on 2 incoming dial tones

I have a client with a Vertical Summit VS-5000-00 that was recently installed. The company that installed it was not very accommodating on troubleshooting a problem that has been here since they put the system in and thus I was asked to take a look. I have had the phone company out to no avail and I am not sure where the issue lies.

There are 8 incoming lines in a hunt group. All lines operate as expected but line 3 and 4. When an incoming call comes in on those lines and then hangs up, the line doesn't release. If you attach a butt set to the DMARC you can hear the phone system answer, then you hear the disconnect signal, but the system keeps playing the welcome message (on the working lines the minute the disconnect signal is heard the message stops and the system releases the line).

We've moved the lines around and the problem stays with the phone number NOT with the port on the phone system. So when we moved incoming lines 3-4 and swapped them with lines 1-2 then lines 1-2 had the problem. Disconnect the phone system and call into the line and it drops and goes to dial tone as soon as the call is ended by the caller so it appears to be the phone system.

Anyone have ANY suggestions? I am about to recommend that they have this company come out and remove this system and have another installed but hoping someone has a suggestion of a setting to change to maybe resolve this?

Thanks in advance for any help and/or suggestions.

Greg Hicks

Sounds like you may have split tips on the pairs. Frog the two tips sides and see if the problem clears. If so I'd ask for two new pairs.

It sounds like the phone company is not sending a disconnect signal on those two lines. You should not hear a "disconnect signal", only a slight "thump" as the voltage is dropped.

The phone company usually refers to this setting as "Cutoff On Disconnect".

With the phone system disconnected from these lines as soon as the caller hangs up the line switches back to dial tone. In fact with a butt set plugged in when you hang up the phone system continues to play the message and you will eventually get a dial tone from the carrier side of things.

The thump is what I was referring to, you can hear the click of the line dropping on the carrier side, but when plugged into the system (auto attendant) keeps droning on.

Here is a dump of the real time device monitoring screen. I just called into one of the trouble lines (Line 7 now) and I see that further down the table, Classification VSF, Type VMIU, Logical Num 1-4, IP 10.10.10.2, shows Line 4 as in use????

Since we moved these lines in the system from 3,4 to 7,8 and the problem follows I think it could be with the providers lines. How do I get them to acknowledge that?

Sorry Bill, what does Frog the two tips mean? One of these pairs was switched this morning so I do not think that is the issue. I am beginning to wonder if there is some service attached to these particular phone numbers (call waiting?) and that is causing the problem?

Thanks guys! I really appreciate your input and guidance.

Classification Type Logical Num IP Address Version Connection State
CO LCOB4 1 - 4 10.10.10.2
R1.1.9 Connected [1:Idle][2:Idle][3:Idle][4:Idle]
CO LCOB4 5 - 8 10.10.10.2
R1.1.9 Connected [5:Idle][6:Idle][7:Use][8:Idle]
CO LCOB4 9 - 12 10.10.10.2
R1.1.9 Connected [9:Idle][10:N/A][11:N/A][12:N/A]
CO VOIU 13 - 20 10.10.10.2
R1.1.9 Connected [13:Idle][14:Idle][15:N/A][16:N/A][17:N/A][18:N/A][19:N/A][20:N/A]
STA DSIB12 100[LDP 9030D] 101[LDP 9030D] 102[LDP 9030D] 103[LDP 9030D] 104[LDP 9030D] 105[LDP 9030D] 106[LDP 9030D] 107[LDP 9030D] 108 109 110 111 10.10.10.2
R1.1.9 Connected [100:Idle][101:Idle][102:Idle][103:Idle][104:Idle][105:Idle][106:Idle][107:Idle][108:Idle][109:Idle][110:Idle][111:Idle]
STA HYIB8 112 113 114 115 116 117 118 119 10.10.10.2
R1.1.9 Connected [112:Idle][113:Idle][114:Idle][115:Idle][116:Idle][117:Idle][118:Idle][119:Idle]
STA HYIB8 120 121 122 123 124 125 126 127 10.10.10.2
R1.1.9 Connected [120:Idle][121:Idle][122:Idle][123:Idle][124:Idle][125:Idle][126:Idle][127:Idle]
MISC MISU 1 - 7 10.10.10.2
R1.1.9 Connected
VSF VMIU 1 - 4 10.10.10.2
R1.1.9
(1:GSA0Fa)
(2:ASA0Cc)
(3:CS10Ba)
(4:GMA0Bb)
(5:IT10Fa)
(6:TK10Ba)
Connected [1:Idle][2:Idle][3:Idle][4:Use]
MCIM Virtual MCIB 1 - 32
.. Connected [1:Idle][2:Idle][3:Idle][4:Idle][5:Idle][6:Idle][7:Idle][8:Idle][9:Idle][10:Idle][11:Idle][12:Idle][13:Idle][14:Idle][15:Idle][16:Idle][17:Idle][18:Idle][19:Idle][20:Idle][21:Idle][22:Idle][23:Idle][24:Idle][25:Idle][26:Idle][27:Idle][28:Idle][29:Idle][30:Idle][31:Idle][32:Idle]

As a note, I was changing the value of the Open Loop Detect Timer in the phone system (CPC) a value of 1 (all values are *100ms) the system never answers, 2 and above and the phone line hangs.

Is there a setting for "Cutoff on Disconnect"? Do I need to mayb e adjust that value?

Cutoff On Disconnect is the telco term. Open Loop Detect Timer would be the setting you adjust. 400ms is what our systems are set at.

If the problem follows the line, then it definitely sounds like a CO problem. You could put a volt-meter on the line and verify that voltage is dropping when the far-end hangs up. You may also want to verify loop current.

Thank you again for the feedback. Do you have a recommendation for a decent multimeter (any of the Flukes probably?) that would give a decent enough reading that I could rely on?

What should loop current be measured at? During ring? Drop amount minimum at hang up?

If all that tests good any other suggestions?

Seems you have to have irrefutable evidence before phone company will even consider that it could be their equipment!

He told me that ALL the lines are hooked up the same so there is no way things could be different on just those two. You want to debate that statement, but at the same time you need to keep him on your side so when you finally do pin down the problem they don't make it more difficult to resolve!

Changing out the system is a bit harsh, like cutting off ones nose...you know the old saying. It may not fix the problem. Disconnect supervision is not working properly on those lines. However there are some adjustments you can make to the CCR which is playing the greeting.

Set the DISA retry count to one or better yet zero so that the message does not repeat after the caller hangs up. In the ccr table that is used to answer the call set the error destination to tone. This will send a howler tone to the co and kick off the line.

You may need to get the installation company back out to do this for your customer.

If the problem happened on 3&4 and on 7&8 once you moved them, it is a problem with the line itself (a carrier issue), and not the system. NFC is probably right about disconnect supervision not being turned on or a voltage issue. Have a vendor meet on-site with the carrier and prove it to them.

If I read his second post right disconnect is working with a butt set. I didn't ask but assumed these are pots lines, if they are CPC is not set on a per line basis, it's per switch line group, so I can't see it not working on just two lines, that's why I suggested spit tips as this will cause this and other weird problems. Being an old fart my assumption of POTS might be wrong.

Disconnect one line from the system and see if the remaining line works properly, my bet is it will.