cut-off on disconnect (cod signal) - please enable
FacelessUser
Enthusiast - Level 3

When I installed my phone system on my copper line I needed to contact Verizon to enable the COD (cut-off on disconnect) signal.  This is the signal which lets the phone system know that the call has been terminated.  Without this signal, the phone system will on occasion fail to hang up.

I recently switched from "copper" to FIOS "analog" phone service.  My phone system is exhibiting the problem with hanging up once again, making me think that the COD signal is no longer enabled for my account.

I wrote to customer service who responded that I should call them instead.  From past experience, this indicates that customer service has no idea what I am talking about and does not know how to route my request... but, doesn't want to say that in writing.

HELP please.  If anyone from Verizon is listening and knows what a COD signal, please feel my pain.  Thanks.

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GaryDoug
Specialist - Level 1

Since you had the problem before you switched service, I have to assume the source of the problem is with your phone system/devices. How many and what type devices do you have? Phones, ringers, fax machines, flashing lights, etc... Try removing them one at a time and see if the problem disappears. Also check for any surge suppressors on the line that may be shorted or leaky.

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A phone service has to be able to detect the difference between the on-hook and off-hook condition in order to connect or disconnect the line. If it can't, then the system does not operate properly, either hangs up prematurely of won't hang up at all. It detects the condition by sensing the current drain or load on the line; too heavy a drain or too light a drain and the system reads the incorrect condition. The drain normally increases when you lift the receiver (off-hook) or decreases when you hang up (on-hook). My guess would be that you have too heavy a drain. Each device has a label that indicates it's individual drain or REN (ringer equivalency number). This is based on a value of 1 for a typical old-fashioned ringer phone. Digital phones usually have a number less than 0.3. The phone system can support a total amount that depends on the design, usually from 3 to 10 total. You can see that there was once a fairly low limit of how many extensions you could have.

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As for the "cod", I guess that the tech had a way of adjusting your standard drain threshold to accomodate your system. That may or may not be true for fios. You should ask yourself why your system needs a special setup to function properly and address that at the source (your devices).

About a year ago when I had the old phone (POTS) service. I had the opposite problem with the line going on-hook. That turned out to be a defective device in the phone company's switch panel down the street. With fios, I doubt that Verizon uses the same switching technique or hardware, but I am not sure. 

If you are technically inclined and have a voltmeter/multimeter, you can test the line drain yourself. It should read about 48 Volts DC when all phones are on-hook and should drop to under 12 Volts DC when a phone is off-hook. Do not touch the line, it can surge to 100 vac when the line "rings".  It is low current, but nevertheless can give you a very uncomfortable shock.

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lasagna
Community Leader
Community Leader

If I'm not mistaken, all the switch circuitry is now inside the ONT since it's what needs to drive the voltage on the copper portion of the line.   I also remember reading somewhere (may have been the specs on the ONT itself) that it will support up to a REN load of 5.0.

I agree with GaryDoug ... if you need to have "special" tuning done for this, either you have a huge number of devices (you don't say how may phones, etc. you have on the wire) or you have a defective device / wiring.   Taking GaryDoug's advice and unplugging everything and then plugging in one device at a time to see if the problem abates (and noting when the problem comes back) should pinpoint the source of the problem.

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GaryDoug
Specialist - Level 1

I haven't seen the specs but I do find "Verizon Fios REN" all over the internet giving a number of 5.0, so it must be true 😉

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lasagna
Community Leader
Community Leader

Well then ... we know everything posted on the Internet is always true ... so you are most definitely right in your assessment.  Smiley Very Happy

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