Faxing over T1?

Discussion in 'General' started by fishfilet, Mar 25, 2010.

  1. fishfilet

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    I am thinking of getting a Sangoma A200. We have a fax machine we need to hook up to Elastix. Elastix is going to be set up with SIP trunks going over a dedicated T1. I was thinking that I would have to have an analog POTS line for faxing.

    On Sangomas product page though it says this.

    So does this mean that I wont need the analog line or is this a different T1 than I am thinking. Is a Voice T1 different from an internet T1 with SIP trunks.

    Right now we have a PRI but we are going to get rid of it.
     
  2. fishfilet

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    I dont now if I am answering my own question or not.

    From looking around it looks to me like a PRI which we currently have is in fact a T1. I did not know that. This is probably what the T1 card is for no? If I want to hook for instance my current PRI into my Elastix PBX I would need a T1 card. But if it is a data T1 I wont need one right?

    If that is the case will faxing still work without the separate analog line going over SIP on a data T1?

    I am guessing that it is sending a fax over SIP that is a problem.
     
  3. rollinsolo

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    if you follow Elastix without tears and set up the Fax Modems as instructed using SIP is not an issue. Your T-1 is data only just like a local cable company, Verizon FIOS etc. Its just internet bandwidth. So no you do not need any T-1 cards to have your system operate. If you have a PRI which runs over a T-1 then you will need a card. If you don't need voice combined with a T-1 why keep it at all, is there any better (cheaper) and higher bandwidth options available to you?
     
  4. dicko

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    Technically a T1 should now be called a DS1 (data service) the T in T1 originally meant telephony.

    Over the DS1 (T1) is provisioned a service, there are 24 x 64kb/s slots (1.54 mb/s) each and every one can carry different payloads, for Telephony originally 24 channels where used to synthesize 24 channels of "phone calls" but the length of the dtmf and fsk tones used for dialing caller id message waiting etc. lead to ISDN (Integrated Services Data Network) in the DS1 version one channel (in the AT&T land it is channel 24 and is known as the Data channel and all calls are set up and torn down (signaled) in this channel, the other 23 are usually used called bearer channels and carry the audio payload.

    There are variations (for example fractional) that will only use some time slots and some uses where some channels are used for data and some for voice. but that's another story.


    So the answer to your questions is that all depends on what you have :) you definitely have a DS1 (T1) but on that might ride "legacy" 24 channel robbed bit signaled voice (often a SuperTrunk in NANP land) but it might be a PRI (ISDN Primary Rate Interface), you will always need a "card" of some sort (CSU/DSU) and Digium/Sangome/Rhino cards act as that piece of hardware, what "rides the T" can be handled by these hardwares be that 24/legacy PRI or pure data.

    Hope I helped and didn't confuse too much, but you will need to dig a bit deeper to knowq what you have and how to use it

    dicko
     
  5. rollinsolo

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    I only said what I did because he said he was getting rid of the PRI (voice portion) of the T-1 Leaving Data only, and unless hes using MPLS to connect to other sites or its the best bandwidth option he has available then I was asking why keep it for data only all together.
     
  6. dicko

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    If he has a PRI, he will need the T1 reconfigured for data (the Telcos wont do that they will require a new install), he can't do that himself, he can set up the PRI for PTP communication to an ISP that supports ISDN connections using his 64kb channels, they will be charged as "phone calls". but that is another really longer story.

    The telco end of a T1 will terminate in very specific hardware and it will be either a data circuit or a voice circuit (or VERY rarely, something that can do both but only by channel and arrangement with the provider), they are very far from the same thing.
     
  7. rollinsolo

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    But to handle fax machine, if you have a multifunction printer/scanner, you can print to fax documents that you scan in using Elastix and YajHFC (windows Java client.) and there is no need for a fax machine altogether, or an analog line either. If you must have an analog line, then when you call in to tell them to keep their PRI portion of the t1 then tell them to break out one analog line onto a channel bank for you or a 66 block.
     
  8. dicko

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    To prevent confusion:

    A single PRI (almost always) in the US rides on a T1, if you have dozens of PRI's then probably not.

    If you want to hook your PRI (if it indeed is an ISDN PRI and not a legacy voice T1) yes you will need a hardware card to connect it to your asterisk box. , (If it is in fact a legacy T1, then still yes but a different yes)

    If it is a data T1 then it won't carry phone calls directly and never did.

    If it currently works carrying Phone calls to a legacy PBX , then yes you can replace your PBX with Elastix/Asterisk, if it is currently used for data alone, it would make no sense to connect it to your Elastix Box.

    And yes if it is a data T1 then it will likely just be to an ISP (perhaps the Telco itself) and use internet protocol and subject to the same constraints as FOIP.

    dicko
     
  9. rollinsolo

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    I agree with Dicko but Fishfilet if your getting rid of the voice portion of your T-1 then you will not need a T-1 card and if you want to use SIP for faxing you will need an FXS card (I think) to give your fax machine dial tone to fax out (if you must use a fax machine), Just dont want you to buy a Sangoma T-1 card and find out you did not need it. Good luck.
     
  10. fishfilet

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    Thanks guys it looks like I dont need the T1 card as my Elastix PBX will be hooked up with ethernet and will have SIP trunks provided from a DS1 (data T1).

    The reason we are getting a DS1 instead of having our SIP trunks go over less expensive connections like DSL or Cable is Reliability and Quality. I see our telephone system as a mission critical system just like my email server. The DS1 has 99.999% uptime, very low latency, yada yada yada
     
  11. rollinsolo

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    Fish, I just use a scanner to file on pc, and fax out with YajHFC via Hylafax (Elastix Faxing) and incoming is handled through Elastix as well. Try it that way first (the Free way, the Open source way) and if you dont like it go buy an analog card, it does not have to be sangoma it could be openvox, I see no difference other than price, and hook up your fax machine.

    Then again if you got money to burn, go for it buy some cards and learn how they work, but I will not guarantee that your sip faxing will work with the card and fax machine. I tried to use a granstream handytone 286 for this and it didn't work for me, it turned me off from getting and fxs card but now that I have had so much time to reflect I would feel pretty confident that it would work.

    As far as that T-1 goes the SLA's provided by them regarding jitter, buffer etc, are regarding to their voice and data packets going into and leaving their circuit in a combined state. If they provide the voice then they handle the QoS that goes into your office. If you take away the voice with them, they are no longer responsible for any QoS regarding voice any longer. So Unless you are ordering the sip service through the T-1 Provider, and you just order an outside VoIP company to handle your voice trunks your T-1 provider will just see them as data going in and going out so now your quality will be limited to 1.5Mbps in and 1.5Mbps out of your office. Good G711 voice calls need close to 100K per call. If your downloading a large file on a 1.5 pipe your voice calls can suffer degradation. Something to think about regarding getting rid of A pri. As well depending on the carrier like the ones I sell, its not much cheaper for a data t as opposed to a data/voice T.
     
  12. rollinsolo

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    Also if your going to order a standalone analog line, why not just plug it directly into your fax machine, why the need for the card at all.
     
  13. fishfilet

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    lol, why didnt i think of that. I have spent some much time reading about what I need I am making it way more complicated than it needs to be. We only have the one fax machine so why waist the money on the card.

    The only benefit I can see from a card now is if I want to set up elstix as a fax server with Hylafax so we can eliminate the fax machine all together but I am not sure if I want to mess with that right now or not.

    As far as the services we have now I dont think I was specific enough. We have a full PRI Voice only that goes into out current PBX. We also have a DS1 (Data only T1) which we use for internet connectivity.

    The DS1 is about $200/month the PRI $800/month. So we are going to get rid of the PRI and get another DS1. We will run our PBX with SIP trunks over this new DS1 now share the same DS1 we have now. This new DS1 will be dedicated to our PBX. Do you foresee any QOS issues now that you know that?
     
  14. rollinsolo

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    Yes as a rule of thumb the more specific you are on here is the more detailed answer you will get, In Florida I sell dynamic T-1's that combine both Voice and Data on one pipe and they QoS is performed on the cisco 2400 series IAD.

    As far as QoS issues if you have a full 1.5 up and down for voice only and using the standard G711 codecs (ulaw) then you have 100k per phone call. so you can comfortably have 15 calls going at once. (12 to be safe). If you use that pipe for something else that constantly interferes with the bandwidth both up and down you could suffer packet loss. depending on how many trunks in use you average under that amount you will be safe.
     
  15. rollinsolo

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    Just a reminder once more, to use Elastix as a fax server there is no need for an analog line or a card altogether, I can send and receive faxes just fine and have neither an analog card nor an analog line coming into my office, only a multifunction printer/scanner that I use to scan the docs.

    But if you got money burning a hole in your pocket for that analog card then get it.
     

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