Base VoIP (Voice over Internet Protocol) technology, which carries telephone calls over the internet, has been around for a couple decades. It's been packaged various ways to address particular needs: make cheaper international phone calls, provide more features –especially virtual numbers and groups– to businesses, and so forth. Lately it's being widely used as a replacement for traditional copper wire home telephone wires (POTS [Plain Old Telephone Service]).
One of the most well-known providers of VoIP as a replacement for traditional home telephone lines is Ooma. They've been in the VoIP business for quite a while, and their business strategy tends toward high volume–low maintenance, so getting personalized/detailed help to replace a traditional telephone line is not always as easy as the user might wish. Accordingly, here are some hints (in addition to all the documentation provided by Ooma itself) on installing their system, which is based around their Telo device.
(These tips were accurate as of October 2021, but may no longer exactly match, as the Ooma website and services can change rapidly.)
The Telo boot/reboot process can be very slow, sometimes taking literally a hundred seconds. Be patient; don't give up before the Telo does. If you give up too soon, you will never complete the installation. While the startup usually goes through only a few stages, it's not unheard of for the status light on top of the unit to glow solid red, then slow flashing red, then fast flashing red, then solid red again, then slow flashing red again, then fast flashing red again, then solid red once more, then finally blue.
In odd specific circumstances, it's possible for the Telo to complete its startup process but not actually be fully functional. This seems to happen when the ethernet connection indicates it's ready before the internet connection is functional. More specifically this seems to happen when the Telo is connected to an independent network router which in turn is connected to a separate (not integrated) cable internet modem, there's a power outage, and the Telo becomes ready before the cable internet modem does. If this happens and you pick up one of your phones, you will just hear silence rather than a dialtone. The fix is to simply force the Telo to restart again; unplug its power connection, wait a few seconds, and plug it back in, then wait a minute or two until the Telo status light turns blue indicating it has completed its restart.
The Telo instructions say very clearly over and over that i] making sure your Telo works, ii] porting your existing landline number, iii] physically disconnecting your old phone line, then finally iv] connecting your Telo to the extension phone lines inside your house, must be done one at a time and in this strict order. Do not deviate.
Since you cannot initially connect the Telo to your inside wiring, you will need to temporarily dedicate a telephone plugged directly into the Telo. This can be a spare phone, an emergency phone, or one of your existing extension phones unplugged from its usual location. This is only temporary; you will not need an additional phone for more than a few days. Doing it this way allows you to get the Telo working satisfactorily before disturbing your existing phone service in any way.
Both early and late in the installation, be sure the old phone line from outside and your new Telo are never connected to same wires at the same time. Find the connection from the old outside phone line to the phone wiring inside your house, and physically disconnect it before you connect the Telo to your inside wiring. Even if you face the inconvenience of using a tool you don't have handy to loosen a couple awkward connector bolts to slip out some hard to reach wires, do it. Be sure the old telephone wire from the outside can no longer touch your inside wiring before you attempt to connect the Telo to your inside wiring. (If the old outside phone line connects to a lightning arrester, leave those connections in place. Just be sure to completely separate your inside telephone wiring from the lightning arrester.)
The Telo instructions also say you should wait one full business day after your old number is ported (transferred) from your old phone company before cancelling your service. Again, do not deviate, as you can wind up with a lost phone number or no phone service at all.
Often, if you had only telephone service (no DSL etc.), your old phone company will cancel your service as soon as they port/transfer the number to Ooma, as no services remain. But not always. Be certain your old service is fully canceled so you don't get another bill from the old phone company next month even though their wires are no longer doing anything useful.
The Ooma Telo is more subject to electrical interference than some other typical home electronic devices. Many sorts of electrical interference might have significant effects.
There may be powerline noise, either through the power adapter itself or through the air, either from a point source such as a motor or hum from the general background. There may be noise from the power supplies in other devices, either electrical impulse noise or magnetic fields. There may be noise that propagates through the air, such as impulse noise from a fluorescent light fixture or RF (Radio Frequency) noise from other devices such as cordless phones and baby monitors. And various types of electrical interference may get inside the Telo through its connection to the house telephone wiring.
The inadequately explained Ooma default dialtone can be quite confusing. It's actually composed of two sounds, a beginning chime and an ongoing insipid hum. This is significantly different than the POTS (Plain Old Telephone Service) that's being replaced, so it may be disconcerting. It's easy for example to misconclude that the chime is the whole dialtone, and the ongoing hum is just some sort of unwanted noise.
Electrical interference can combine with the ongoing dialtone hum to produce a sound that's much like a dialtone but not quite right. The sound is neither clearly noise, nor clearly just dialtone.
At any time electrical interference can manifest as a continuous hum (often sounding like a dialtone) rather than as the expected sound.
Customers and advisers —and even Ooma's technical support— often do not distinguish different types of noise, something that could and should have been done simply by noting when the noise is heard. This needless confusion of different types of noise usually results in focusing on a non-issue and missing the actual problem. The resulting experience is fustrating to everyone.
Trying to give telephone traffic priority over other internet traffic by manipulating the QoS (Quality of Service) tags often makes no noticeable difference (despite possibly interfering with some other internet uses such as playing video games).
If possible change your Telo's dialtone to the typical POTS one before you even start installing it. (Or at least be aware of what it is you're hearing, and don't misinterpret the Ooma dialtone as noise.)
To change the dialtone, first log in to the Ooma website (my.ooma.com). From the dark blue banner at the top of the screen pull down the Preferences menu and select Devices. You'll see one or more boxes containing phone numbers and a picture of a Telo. Just below the picture of the Telo device it will say Telo and also display a small light blue gear. Click on that gear, then when another menu appears click on Edit (probably the top item). A popup screen will appear containing four items: DeviceType, Name, Mode, and DialTone. Focus on the fourth/last one, DialTone. Click on the small downward-facing triangle inside the box near the right end. A menu will appear presenting two alternatives: Ooma(Default) and Regular. Click on Regular. Now click on the bright green Save button in the bottom right corner of that same popup window.
Situate your Telo a few feet away from other electronic devices, especially your router, your WiFi base, and any cordless phones. Also place your Telo away from any rats nest of power cords. [If noise, do this first!]
If you are concerned about some noise, note carefully when you first hear it: immediately along with the dialtone on picking up the phone? a bit later when the other phone is ringing after dialing? or much later after your call has been answered and you are attempting to converse? Make sure any technician assisting you understands what you are hearing and when. Just calling it noise is too ambiguous, and may not lead to a solution.
If you hear a noise immediately, it is local electrical interference from your house getting into the Telo; trying to improve voice quality is a waste of time as it will will have no effect on this type of noise. If you first hear a noise during ringing (after dialing), it probably has something to do with your router or internet cabling. If you first hear a noise when conversing (after the other phone has been answered), you have a voice quality problem that's probably somehow caused by your internet service.
Ground your Telo. [If still noise, do this second.] Connect one end of a wire to your house electric power wiring's ground (the green ground, not neutral and certainly not hot), perhaps by loosening a cover plate screw on a receptacle, slipping a wire around it, and tightening the screw back down (but not so tight it deforms the cover plate).
Connect the other end of the wire to the Telo. At first this may look difficult, because the Telo has no ground connection nor ground wire, its inside is not accessible, and it doesn't even have any visible screws. Fortunately there's yet another way to make contact with the Telo circuit board ground: use the shield (the outside, not the negative power lead/black wire) of the USB port. Obtain a short good quality USB data cable (you can't use an unshielded USB charging cable for this), shave some of its insulation away so you can access the shield, attach the other end of your ground wire to the shield, and plug the USB cable into the Telo (the other end of the USB cable will remain unconnected).
If your internet connection is fast, and your Telo is connected bewteen your modem and your router (and that's already a big if:-), temporarily configure the prioritization/QoS within your Telo to 0s and offs so the prioritization of telephone traffic is disabled. Then make some calls. If voice quality hasn't suffered, leave the prioritization/QoS turned off permanently; configure it back the way it was only if the voice quality was noticeably degraded by your test.
Manipulating QoS made good sense with the typical internet speeds of a few years ago. But with current faster internet connections (any service with near or over 100Mbs upstream), it's no longer needed and in fact may cause more trouble than it cures.
Shield your Telo. Get a conductive metal cooking tray (for example a disposable heavy aluminum foil tray). Stand it on edge between your WiFi base or other equipment and your Telo. Connect the ground wire from the previous item to the tray using an additional screw, as well as to the Telo via the USB port.
In the worst case, an alternative is to get two different sized conductive metal cooking pans (for example disposable heavy aluminum foil pans). Turn the smaller one upside down inside the larger one. Hide your Telo in the space between the pans. Connect the ground wire from the previous item to both pans using additional screws, as well as to the Telo via the USB port.
Fortunately this is very seldom needed, as it removes the Telo colored status light from view and makes the Telo voicemail and volume buttons inaccessible. Do it only if the noise source is inside your house, and the noise remains even after you've taken all the other steps above.
Use old DSL filters as noise filters. Connect one between each extension phone and the place that phone connects to the wall, just like you did with DSL. (Unfortunately you usually can't just use one DSL filter on the Telo itself, as a filtered Telo is sometimes unable to detect when you pick up an extension phone to dial. So do not include a DSL filter in the connection between the Telo and the wall.)