Verizon Fios

[stevebea]

FiOS voice service (POTS) is not VoIP, (it's a separate optical carrier) neither is cable company telephone. It's packetized digital yes, but only SIP or services like Vonage are VoIP and you will know that because they use the ethernet broadband port just like data.

As to fax not working, I can remember when FiOS was first introduced several years ago Verizon would always keep it on the old copper POTS, not a FiOS line. So they knew that there were problems.

-Hal

So FiOS voice is neither POTS or VoIP but is digital voice, correct? Thanks.

 

[Electric-Light]

Commercial internet service cost substantially more partly because of the up-time clause in service agreement. Residential service doesn't have such a guarantee. I don't remember the last time my POTS went down. The internet? Here 'n there, sometimes many many 10 minute outages in a day. Every once in a blue moon, out for a few hours.

ISPs usually get to do whatever they want. As far as I know, they're not regulated under the PUC like telephone, water, electricity, gas and other "utilities".

 

[hbiss]

So FiOS voice is neither POTS or VoIP but is digital voice, correct?

No. As far as anybody installing phone wiring is concerned it absolutely is POTS. Only difference is that it isn't delivered via miles of copper wire from the central office. It is delivered from the central office digitally via miles of fiber then converted to POTS by equipment (ONT) that replaces the usual DEMARC gray box. Really nothing has changed, it's fiber in/copper out instead of copper in/copper out. The FiOS optical network terminal has POTS connections the same as a DEMARC and gets connected to the same exact way.

-Hal

 

[stevebea]

So FiOS voice is neither POTS or VoIP but is digital voice, correct?

No. As far as anybody installing phone wiring is concerned it absolutely is POTS. Only difference is that it isn't delivered via miles of copper wire from the central office. It is delivered from the central office digitally via miles of fiber then converted to POTS by equipment (ONT) that replaces the usual DEMARC gray box. Really nothing has changed, it's fiber in/copper out instead of copper in/copper out. The FiOS optical network terminal has POTS connections the same as a DEMARC and gets connected to the same exact way.

-Hal

Thanks Hal, I was having a bit of a problem wrapping my mind around this.:roll:

 

[nhfire77]

So FiOS voice is neither POTS or VoIP but is digital voice, correct?

No. As far as anybody installing phone wiring is concerned it absolutely is POTS. Only difference is that it isn't delivered via miles of copper wire from the central office. It is delivered from the central office digitally via miles of fiber then converted to POTS by equipment (ONT) that replaces the usual DEMARC gray box. Really nothing has changed, it's fiber in/copper out instead of copper in/copper out. The FiOS optical network terminal has POTS connections the same as a DEMARC and gets connected to the same exact way.

-Hal

Then why doesn't analog modems work so well with it? Such as a FACP?

 

[zbang]

Then why doesn't analog modems work so well with it? Such as a FACP?

The problem might be that the line is too good. Most terminal devices ("CPE"- customer provided equipment) are built expecting about 50 volts open circuit dropping to <10 volts and <50ma "off hook" (it's the thousands of feet of 24g wire). When the ONT or other provider is so close, it can supply too much loop current and the audio signal can be too high. Haven't seen this with an ONT, but the Lucent narrow-band shelves and the SLC96 both had these problems. The solution is often something simple like a 300 ohm resistor in each line of the pair. If you have a lot of POTS lines, sometimes the telco engineering folks will back off the audio level and current- had to do that for about 200 lines into the modem racks of an ISP. They were about 30' from the SLC.

More info at Mike Sandman's site: http://www.sandman.com/loop.html.

 

[hbiss]

When the ONT or other provider is so close, it can supply too much loop current and the audio signal can be too high.

That's not the reason.

Then why doesn't analog modems work so well with it? Such as a FACP?

For the same reason faxes are hit or miss also. The very simple explanation is that digital services like this are made to handle voice. Analog voice or audio, when converted to digital produces very random strings of data. Modems and faxes are already digital and when re-converted the data is much less random. The conversion process that is used also compresses the data and drops trailing strings of 1s or 0s. That's not a problem for voice because repetitive strings of 1s or 0s aren't common but they can be for modems and faxes.

-Hal

 

[Electric-Light]

So FiOS voice is neither POTS or VoIP but is digital voice, correct?

No. As far as anybody installing phone wiring is concerned it absolutely is POTS. Only difference is that it isn't delivered via miles of copper wire from the central office. It is delivered from the central office digitally via miles of fiber then converted to POTS by equipment (ONT) that replaces the usual DEMARC gray box. Really nothing has changed, it's fiber in/copper out instead of copper in/copper out. The FiOS optical network terminal has POTS connections the same as a DEMARC and gets connected to the same exact way.

-Hal

Even ordinary "landline" POTS are digitized through a multiplexer box which splits up a digital service into POTS. Fairly common in rural and suburbs. A single T1 line can be broken into 24 standard voice lines. Unlike old school method, it does not require a pair of wire per phone number served all the way back to the central office. I don't know much about their configurations, but the number of lines served probably exceed the number of lines available much like electrical load utilization factor which means the transformer will be smaller than the total service kVA attached to it. These telco furnished systems are designed to provide POTS and have UPS inside so it provides service even during outage. These lines fall under PUC regulations.

Older multiplexer cabinets does not have ADSL support and this will prevent you from being able to get DSL. Newer multiplexers provide support for DSL as well and they're called DSLAM.

FiOS box is much like Vonage with the POTS provided by a box on customer premise.

 

[zbang]

When the ONT or other provider is so close, it can supply too much loop current and the audio signal can be too high.

That's not the reason.

I said that it's -a- reason and the cited examples were for a SLC at an ISP I consulted to. They were seeing 80-100 ma on the loops to the modems. That's way too high. Doesn't take much current to saturate a 1/2" cube transformer. We also had measured audio level problems. It will cause problems.

Then why doesn't analog modems work so well with it? Such as a FACP?

For the same reason faxes are hit or miss also. The very simple explanation is that digital services like this are made to handle voice.

You're referring to the "vocoder" (vocal encoder) that looks for speech-like sound patterns and turns them into digital symbols. Most commonly done in cell phones. SLCs and channel banks don't do use a vocorder but just a straight mu-law encoding (in the N America). No problem with modems & fax machines.

Analog voice or audio, when converted to digital produces very random strings of data. Modems and faxes are already digital and when re-converted the data is much less random. The conversion process that is used also compresses the data and drops trailing strings of 1s or 0s. That's not a problem for voice because repetitive strings of 1s or 0s aren't common but they can be for modems and faxes.

Group 3 faxs are Huffman compressed, so the do have a varying bit pattern and no long strings of 1s or 0s.

The problem is the vocoders (voice encoder). Some VoIP phone devices are designed to recognize fax modem tones, demod them at the sending end, send the bits, and re-modulate at the receiving end (ITU T.38 standard, iirc). Not all "digital phone" devices do this. If the device is T.38 compliant, then your fax should work and the FACP might also. I don't know whether Verizontal FiOS voice is VoIP or some other encoding. Fortunately I'm not in their service area although I can ask someone who is and would know.

 

[nhfire77]

Then why doesn't analog modems work so well with it? Such as a FACP?

For the same reason faxes are hit or miss also. The very simple explanation is that digital services like this are made to handle voice. Analog voice or audio, when converted to digital produces very random strings of data. Modems and faxes are already digital and when re-converted the data is much less random. The conversion process that is used also compresses the data and drops trailing strings of 1s or 0s. That's not a problem for voice because repetitive strings of 1s or 0s aren't common but they can be for modems and faxes.

-Hal

I get its converting, but you said:

Really nothing has changed, it's fiber in/copper out instead of copper in/copper out. The FiOS optical network terminal has POTS connections the same as a DEMARC and gets connected to the same exact way.

So why does it work one way and not the other?

 

[MR2Di4]

I get its converting, but you said:

Really nothing has changed, it's fiber in/copper out instead of copper in/copper out. The FiOS optical network terminal has POTS connections the same as a DEMARC and gets connected to the same exact way.

So why does it work one way and not the other?

Because of the key difference between providing POTS via IP and POTS via T-carrier signalling: Time.

T-carrier backbones and their equipment are very dependent on constant time-division multiplexed communication, sometimes even a separate timing unit is linked to T-carrier racks to ensure that the frames of data being sent and received go where they're supposed to in the proper order and at the proper time. (We're talking microseconds here...) Hence, switching is very accurate and supposed to be 99.999% reliable on a clean circuit, which means that the encoded data from things like faxes gets where it's going without distortion or loss.

VoIP systems are less constrained since they rely on packets via TCP/IP which has retransmit and error correction built in to ensure that all the data gets where it's supposed to go, however it's not as stringent as to when it gets there. If a packet of data (phone call, fax data, Internet, TV stream, whatever...) is lost then a request for retransmit is automatically sent but even with current data buffering technology there is potential for lost data. Someone browsing the Internet probably won't notice, TV streams may experience a smidge of tiling, but fax communications aren't nearly as tolerant. They tend to either fail altogether or users experience missing page data. Same goes for credit card machines, although the amount of data actually sent/received is much less so they aren't nearly as problematic.

My company has recently completed a conversion from our old DMS-100 switch to a new "soft" switch running VoIP. During the transition period a couple years ago, I had just finished up a month of working graveyard shifts swinging the POTS lines for mostly downtown business customers to new VoIP based equipment at the remote office, just before the busy tourist season began. The first business day was a disaster! Proprietors were in a fit as they couldn't run credit cards for transactions, faxes of orders never made it out and alarm panels lit up like Christmas trees. I remember shaking my head as the Central Office Engineer frantically called the equipment vendor for possible solutions and our techs were back in the same office throwing lines back onto the old equipment. (Not enough testing had taken place beforehand, just going on the vendor's promises...)

The solution came finally when we were able to tie the old remote equipment to the new switch via recently tested patch codes, but it still isn't perfect. Most businesses went to newer Ethernet/Internet based card readers and although faxing is still an issue, most multifunction office printers now scan documents to .pdf forms that can be attached to e-mails. There are still holdouts clinging to their fax machines and dial-up devices, but it's safe to say that the era of traditional "modem" devices is in it's twilight.

 

[Open Neutral]

Any call you make today [in the US] starts out analog, gets digitized, and is delivered as analog.

The devil is in the details.

POTS, as defined by most people, is delivered as analog to the CO, over 1 pair. There, the line card digitizes it and it is all bits from there. In the highly unlikely event you are not now served by a digital switch, then it's digitized on the trunk side before being shipped over to Hooterville or Peoria. There is no analog trunkage left.

[Trunks run from switch to switch; lines run from end users to a switch.]

ISDN-BRI moved the A-D conversion from the CO to your phone; the analog part is reduced to the handset & cord. This is also true of most business PBX systems.

FIOS uses analog phones but does the A-D in the ONT in your garage. They still call it POTS but....

VOIP does the conversion at your desk.

In the case of a cell phone, the analog part is even shorter; from the transmitter {mike} to the A-D is a few millimeters.

The devil is: is the call guaranteed bandwidth as FIOS, PRI etc. does; or is it "best-effort" over a ComCrap TCP/IP feed? What standards applied to the A-D? You do it cheap & skimp on bits {cell phones and VOIP} or deliver good quality [POTS, ISDN, etc.]

FAX is an abomination. Digital data [typed words] are converted to analog [print images]; scanned and digitized, then THAT data is converted to analog modem tones to be redigitized by the phone network for transmission. Is it any wonder...?

In general, POTS offers the worst possible supervision aka call origination/control/answering. POTS uses loop current to sense activity, DTMF tones to dial, 20Hz to ring, etc. Others use a dedicated out-of-band management channel.

POTS does, however offer central office power; as long as the CO has -48V, your phone will too {barring cut lines...}. And IT has a big honking battery bank and Diesel.

But wait! A SLC aka DLC moves the POTS A-D to some box in your neighborhood & runs fiber to the CO; that saves Ma lots of copper but few have more than 3-4 hrs. {promised} battery supply.

YMMV.