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kerrydeare

join:2012-08-29
Trenton, NJ

[FiOS Phone] VZ Digital Voice Voltage Characteristics

I am investigating cellular backup for home security. I use a VZ Digital Voice line that sends CID data to a monitoring station. Since it ultimately depends on either AC or a backup battery, I am considering a cellular system as a secondary backup.

Question: If the FiOS Digital Voice line is accidentally or intentionally damaged, what then happens to the 48 VDC that is ordinarily across the interior telco line? Specifically, if the fiber is cut outside the dwelling, does the ONT still maintain the 48 VDC across the inside phone lines (using either house 120 AC or the battery backup)? The point of this question is that the cellular backup only operates when it detects no voltage over the house phone line. It of course doesn't actually "know" that a notification failed, only that the primary line itself is not working per specification.



Smith6612
Premium,MVM
join:2008-02-01
North Tonawanda, NY
kudos:23

Pretty sure the voltage will be there, you just won't get a dial tone. I'm probably wrong, however.



danclan

join:2005-11-01
Midlothian, VA
reply to kerrydeare

I am going to out on a limb and say if your ONT loses signal it would continue to power all the feeds in the home like Smith also stated - ethernet (if active), coax and phone but would give you constant busy signal or no signal reports on the TV.

The only time I would expect the cellular backup to kickin would be ~6-8hrs after a power loss and drain of the batter backup. I would invest in a larger secondary batter backup for the ONT power supply myself rather than a cellular backup.


ajricaud

join:2002-02-04
91745-2638
Reviews:
·DSL EXTREME
reply to kerrydeare

Unfortunately, the cellular backup won't know if the fiber has been cut until the ONT's battery runs out. Adding more battery capacity only extends the time that the system is down before a failure is sensed. The backup needs to work when it senses no dial tone OR when there is no power.


kerrydeare

join:2012-08-29
Trenton, NJ
reply to danclan

said by danclan:

... The only time I would expect the cellular backup to kick in would be ~6-8hrs after a power loss and drain of the batter backup ...

According to the Uplink literature, the device monitors phone line voltage when in the "on hook" state, and phone line voltage and current in the "off hook" state. The latter corresponds to making a call. In the situation in question, the Uplink could possibly notice that while the voltage exists, the zero current state (i.e., cut fiber) is an error condition.

This is pure speculation on my part, but that's all I have to go on just now.

Hooper
Premium
join:2001-10-22
Villanova, PA
reply to kerrydeare

If you don't already have the alarm system, have a look at lifeshield. I have disabled the phone line completely in the unit so it thinks I don't even have phone service. Alarm monitoring is over internet or cell. If fiber is cut and/or power disconnected, the cell gateway can still dial out (or transmit data in reality).



FFJOHNL312
Premium
join:2007-12-16
Pawtucket, RI

1 edit
reply to kerrydeare

The TL;DR answer:

As long as the ONT is powered, the voice ports will have -48vDC on them, even if there is no fiber attached to it. Whether it has dial tone or not, when fully connected, is a matter of programming.



HarleyYac
Lee
Premium
join:2001-10-13
Allendale, NJ
kudos:2
Reviews:
·Verizon FiOS
·Verizon Online DSL
·Optimum Online
reply to kerrydeare

Hi,
Slightly off topic. My Ont is outside susceptible to intentional damage. I have ADT am no longer in contract. I advised them I am switching providers . With that said they gave me Cellular backup with no monthly increase. .. YMMV
Lee
--
My opinion on religion and science? Science builds airplanes. Religion flies them into buildings.


kerrydeare

join:2012-08-29
Trenton, NJ

Interesting but not wholly surprising. These "guys" (Verizon. Comcast, ADT) spend many dollars to acquire new subscribers, so we should not be astonished to hear that they will spend a bit more to retain them.



HarleyYac
Lee
Premium
join:2001-10-13
Allendale, NJ
kudos:2