Will SPA112 work with LTE cellular router? With fax on LTE cellular router?

[weinmann1]

1. Will the SPA112 work with an LTE cellular router? I'm currently getting about 20 Mbps up and down on our LTE router via a cellular connection.

2. If so, will faxes work on the SPA112 on an LTE cellular router? The one we have has a voice jack, but it's not a VoIP jack - it's uses the cellular voice network. Our fax machine does not work on that. The SPA112 would use the router's ethernet connection.

Thanks.

[Dan Lukes]

SPA112 have Ethernet WAN interface. It don't know the technology behind.

Particular technology can be used if it fulfill VoIP requirements. E.g. almost 100% reliability, low jitter, low end-to-end delay (up to 100ms for standard call, up to 500ms for low quality call). If you have such connectivity, then it's suitable for VoIP regardless it's LTE or not. Particular technology is not the matter.

According fax - it depend on protocol uset by fax as well as protocol used by SPA112 and upstream provider. With compressed codec no fax will work. With G711 the fax up to 9600Bd should work. With T.38 even higher speed may work.

Thus, don't claim the technology name - claim the parameters of the uplink you have. Or we are unable to respond.

[weinmann1]

Thanks for pointing out the duplicate thread. I got an error message that said the system was down on the first attempt to post, so I tried again a minute or two later. Had no indication the first effort went through.

I have no idea how to give you "the parameters of the uplink (I) have". How would I test this?

And I do think the particular technology matters. As I understand it, the voice protocols used by cellular providers (which I would consider a "technology") work in a way that does not, and cannot, work with fax, regardless of the speed, quality, or reliability of the connection. As a result, the voice line on my router won't work. (By contrast, I understand that faxes could be sent over the old analog cellular system if you had a strong signal.)

The same compression techniques are not used by cellular carriers for straight data (vs. digital voice data), so it's possible that fax would work with it. But I do not know whether the IP connection provided by cellular in some other way differs from that provided by cable or DSL, for example. That is part of my question.

[Dan Lukes]

he voice protocols used by cellular providers (which I would consider a "technology") work in a way that does not, and cannot, work with fax

You are not carrying fax as a voice thru cellular network thus no voice protocol is used here. . You use cellular network's data channel and you pass SIP/RTP digital stream thru it. It's SIP voice codec that you are interested in here, not the cellular one.

As I claimed before, if compressed codec used, no fax will work. With uncompressed codec, the fax up to speed 9600Bd may work, if the overall connection is suitable for casual audio call.

Disclose the codec used during call, disclose the fax speed you are using and we can guess it should or it should not work.

Or we can just blind shot. Assuming your VoIP provider supports no T.38 configure your fax not to use speeds above 9600Bd and configure your SPA112 not to use other codec than G.711u (North America or Japan) or G711a (rest of world).

I have no idea how to give you "the parameters of the uplink (I) have". How would I test this?

It depend on resources you have and network topology.

If you have an UNIX like OS connected, use 'ping' to test - configure it to send packet of size 160B every 20ms to your VoIP provider. 8000 packets is like 120s of SIP call. Results of such ping disclose you basic parameters of the line.

There may be a tool for Windows as well, but I know no one.

Well, those tests require at least basic networking skills. Ask nearest LAN technician for help if you don't understand what I'm speaking of here.

I do not know whether the IP connection provided by cellular in some other way differs from that provided by cable or DSL

Just technology name doesn't allow to guess the parameters we need to know. DSL as well as LTE may be good enough to carry VoIP call. But both DSL and LTE may not be suitable for VoIP as well. There's no generic answer based on just technology name possible. Sorry.

[weinmann1]

Thanks. That is helpful. I pointed out about the voice line because you said that "Particular technology is not the matter." But in the context of using what amounts to a cellphone, one of the "particular technologies" I have available is voice. So in that context the specific technology does matter. (And if that worked, I'd not need to look at an SP112.)

This is speculative because:

1. I don't have an SP112 yet. I want to find out if it can work for fax over a cellular connection. Since I found out that fax cannot work over the voice connection, my first question was whether there is some specific reason it couldn't work on VoIP over a cellular data connection. If I understand you correctly, there is no reason in principle why it would not work.

However, as an example, you mentioned "jitter". It is possible that no cellular network (currently) can control its network well enough to lower jitter to an acceptable level. That would qualify as a technical reason why fax over cellular data cannot work. It is possible someone knows the answer to this without me having to do any tests.

2. Because I don't have an SP112, I also do not have a VoIP provider. I would like to get one that supports the best chances of fax working, but I'm not at that point yet. If you have a VoIP provider to suggest, and the URL I'd use for testing, I can try that.

3. I'm self employed. While a relatively quick study, I don't have access to the "nearest LAN technician". Which is why I'm asking for help here.

I am mildly familiar with doing a ping test. I have Macs running Mac OS 10.4, 10.5, 10.6 and 10.11. Apple's Network Utility can do pings, but it only has two options: send XX pings, or send an unlimited number of pings. I do not see a way to adjust packet size or ping interval. This is what I get from pinging google.com:

PING google.com (74.125.141.138): 56 data bytes
64 bytes from 74.125.141.138: icmp_seq=0 ttl=43 time=2021.929 ms
64 bytes from 74.125.141.138: icmp_seq=1 ttl=43 time=183.658 ms
64 bytes from 74.125.141.138: icmp_seq=2 ttl=43 time=113.412 ms
64 bytes from 74.125.141.138: icmp_seq=3 ttl=43 time=61.882 ms
64 bytes from 74.125.141.138: icmp_seq=4 ttl=43 time=321.481 ms
64 bytes from 74.125.141.138: icmp_seq=5 ttl=43 time=325.026 ms
64 bytes from 74.125.141.138: icmp_seq=6 ttl=43 time=125.994 ms
64 bytes from 74.125.141.138: icmp_seq=7 ttl=43 time=234.542 ms
64 bytes from 74.125.141.138: icmp_seq=8 ttl=43 time=104.857 ms
64 bytes from 74.125.141.138: icmp_seq=9 ttl=43 time=152.152 ms

--- google.com ping statistics ---
10 packets transmitted, 10 packets received, 0% packet loss
round-trip min/avg/max/stddev = 61.882/364.493/2021.929/558.935 ms

I am able to follow instructions for using OS X's Terminal, but I don't have very much of its feature set memorized.

Disclose the codec used during call, disclose the fax speed you are using and we can guess it should or it should not work.

I don't know what codecs a fax machine uses. I can adjust fax speed and some other settings. I am not currently in the same location as the fax machine I'd like to use, which is a Brother MFC 8910 DW. I am in the United States. If I knew the answers to all of that, I would not be asking for help.

Another question: Is using T.38 dependent on the fax machine as well as the VoIP provider, or does only the VoIP provider need to support it?

I do need help, and I appreciate your patience with my lack of knowledge. Thank you.

[Dan Lukes]

I want to find out if it can work for fax over a cellular connection.

FAX can work over GSM. You need an equipment allowing you to connect fax to such network, of course. It is neither SPA112 nor LTE router (LTE is about DATA, so it allow you to connect to Internet only, not make casual voice/fax calls).

If you wish not to pass fax as fax but pass it as FAX encapsulated into SIP, the SPA112 may turn fax signal to SIP data stream for you. You need a VoIP provider to decapsulate FAX from SIP stream and pass them as FAX to to target.

It is possible that no cellular network (currently) can control its network well enough to lower jitter to an acceptable level. It is possible someone knows the answer to this without me having to do any tests.

Most of connections available to home/smb users can't control it. Despite of it, users can pass calls and faxes trough their connections. You either have connection suitable for it or not.

But, if you wish for answer with no parameters known, the the answer is NO (to be on safe side).

I also do not have a VoIP provider. I would like to get one that supports the best chances of fax working, but I'm not at that point yet. If you have a VoIP provider to suggest, and the URL I'd use for testing, I can try that.

You overestimating my power to advise a lot. There's no VoIP provider suitable for something at worldwide level. As I mentioned, the quality of connection between you and the VoIP provider is critical parameter. So you need to reject all providers you have no reliable connectivity to them.

There's are no simple answers to so complex question. Even VoIP provider from same street you are living in may be unsuitable for you. For example he is using different data upstream with no fast and reliable connection to the upstream data provider used by your cellular operator.

According fax - you can read marketing materials of particular VoIP provider, you can seek for other users experiences, but on the end you need just to try one.

No way to make reliable conclusion based on fuzzy inputs.

Even experienced technician will guess here - it's chance to hit is higher than yours, but it's still no more than guess-based decision.

If you wish for reliable answer, then no, LTE is not suitable for VoIP. The same apply for xDSL, WiFi - and all other data connection you may have unless the provider of such connection has guaranteed to you the required parameters will be maintained.

I don't have access to the "nearest LAN technician". Which is why I'm asking for help here.

Are you living on desert or so, isn't it ? No jokes, I take it seriously - but you are asking for a kind of magic.

You have neither equipment to test your current connection nor experience required to make tests. I have some experience, so I can estimate, but I have no data to make conclusions from nor chance to get such data from you. So we are in deep shits, sorry to saying it. We can make wild guesses only.

OK, lets go.

Just 10 pings are not enough to measure the line. Based on it - your lime may be suitable for VoIP/FoIP (Fax over IP).. But it's far from perfect, there's high chances you will have issues with it. And your experience level needs to be taken into consideration here, as well as the fact there are no local experts you can ask for help.

Conclusion ? You should not try Fax over IP with such connection. Seek for other technology if available. If no other technology available then try it, but remember it may not work.

it only has two options: send XX pings, or send an unlimited number of pings

It seems you are using a GUI. Most of valuable tools require CLI (a.k.a. 'terminal') skills from you. I have no experience with OS X,so I can't provide exact command to you. 

Well, OS X is FreeBSD based system, so similar command option may work on command line, but if it will not work as provided, you have no experience to find working form.  So forget it.,

Brother MFC 8910 DW

Read the manual and limit Tx as well as Rx speed to 9600Bd max. Consider it generic advice unless you will fax thru classic wire landline.

Is using T.38 dependent on the fax machine as well as the VoIP provider, or does only the VoIP provider need to support it

T.38 is fax-specific codec used to encapsulate analog fax into SIP stream. FAX know nothing about it. The SPA112 encapsulate the analog (fax) audio into SIP data stream. The T.38 needs to be supported on both encapsulating and decapsulating side. SPA12 supports it, but VoIP needs to support it as well.

[weinmann1]

While I still have questions, you have actually helped me a lot. As you point out, it's not just whether the SPA112 can do the best "encapsulation" as you call it, but the quality of the data line in terms of what a fax machine expects in a connection. And while I would expect more interference on a cellular connection than on a digital cable or telephone line, those can be "noisy" too.

I have never heard of a device that can send fax over digital GSM voice, but perhaps that exists somewhere. The LTE router I am using now cannot do it.

I am actually a bit surprised that no one has come up with a device that can intercept a fax call as it leaves the fax machine (it would have to provide a pseudo-fax receiver to answer the fax machine's call, but fax modems have had that for years), buffer it, then convert it into an encrypted internet friendly form. This would need a service that could then unencrypt the data, convert it back to fax form, and dial the receiving fax machine.

There are many "internet fax" companies, but they normally expect you to email a document to them, which they then convert into fax. If you have a paper document to start with, you have to scan it to a computer first, which is a lot more trouble than sending a regular fax.

Thanks again.

[Dan Lukes]

I have never heard of a device that can send fax over digital GSM voice

My former mobile phone has such capability, for example. And I has assigned dedicated phone number for faxing. I never used it for sending or receiving faxes. I assume even my current phone can do it, but I didn't investigated.

If you have a paper document to start with, you have to scan it to a computer first, which is a lot more trouble than sending a regular fax.

Sounds not so plausible. I need to place document on glass - fax and scanner is the same. I need to type target number on keyboard of fax or the computer with scanner. You need to push button "fax" - on either fax or computer.

I consider it the same. Of course, my opinion is not relevant here - you wish to use your existing Brother fax you are familiar with. I respect it.

[weinmann1]

Thanks. As I look around the web, I see that there are places with cellular providers that offer fax options. I found info on this for both South Africa and Australia. This is, unfortunately, not true in the United States. From what I can tell, you need both the phone hardware, and support from the cellular carrier. The U.S. cellular carriers don't provide this support.

As to faxing vs. scanning, it is three steps to send a fax from my fax machine. It's about nine steps to scan a document and send it by email, and more if I want to send it by a secure service that I have to log into on a web browser, and scanning requires I use two machines (scanner and computer) which may not be next to each other. Using the computer's fax modem to send a scanned document would also take more steps. So I think faxing from a stand-alone machine is easier.

Of course this assumes I already have a paper document. If I the document is on my computer, and I had to print it first to fax, then sending from my computer would be faster. But then I wouldn't be using the scanner.

Thanks again.

[Dan Lukes]

The U.S. cellular carriers don't provide this support.

U.S. cellular carriers are not covered by my experience, thus I can't neither confirm nor reject it.

It's about nine steps to scan a document and send it by email

Put paper on scanner's glass and push 'scan to email' button located on scanner. A window asking me to enter email address rise on computer. Once filled, task is completed. It's three step process as you wished. But I'm not trying to push you to change mind. I just wish to be sure you didn't missed a solution.

if I want to send it by a secure service

If you wish for security, forget fax at all. Scanner and computer will allow you to send it secure way only The fax, either via GSM or SIP offer no security.