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Thread: Link your Quantar over IP with some crusty old modems for CHEAP!!!!

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    Thumbs up Link your Quantar over IP with some crusty old modems for CHEAP!!!!

    Since you're all chomping at the bit (and rightfully so), I'll post the important pieces of info. I don't have time to write a lengthy post now, but here goes:

    Equipment needed to make a Quantar talk over IP:

    1) Working Wireline board w/ V.24 daughterboard. Should be running at least SCM R020.010.xxx. If anyone knows what version the V.24 astro connection was well implemented in, please chime in. That's the earliest firmware I had that worked. I tried the V.24 on some crusty old R016 firmware and it didn't work.

    2) UDS V.3225 modems. Can be had the 'bay for cheap. Or I imagine some of you guys might have these things lying around. You should definitely opt for the version with buttons and display- easy to configure and run.

    3) Obihai OBi-100 VOIP adapters (sells for less than $40 on Amazon)

    Basically, you feed the V.24 synchronous serial to the V.3225 modem and then you feed the 2 wire dial line to the OBi-100. I'll post pinouts and settings info later, but this is simple (especially the VOIP adapter part).

    Sounds ridiculously easy, and it is! I decided to experiment with the modem on a whim after seeing this specific model mentioned in an old Quantar Infrastructure Planning Guide. This modem is actually very versatile since it will support 2 wire dial, 2 wire leased line and 4 wire leased line.

    For the most simple way to make them connect to each other, the VOIP adapters come with a built-in direct dialing number which requires no paid service provider (it actually works with the direct # right out of the box and no configuration). As long as you have a connection to the public internet, the Obitalk service will let the two VOIP adapters call each other direct for free. You set the modem up to dial the the direct Obitalk # of the other end. Have it dial the number, the other end rings and then it's an old school modem training symphony for a bit and voila, synchronous serial over IP! I should note that it can take up to 30 seconds for the modems to train and finally lock on. I think this is because of the high latency of the VOIP transport (roundtrip starts around 260ms and moves up from there, even on same switch). I have successfully had the modems connect routing the call through a provider in LA which the roundtrip time was ~620ms. So, I think linking just about anywhere is possible.

    These VOIP adapters are HIGHLY configurable and because they use the SIP protocol, I think it would be fairly easy to get them to use an Allstar/Asterisk server to provide the automatic and configurable connection mechanism. Just think, you could choose what other Quantar you wanted to link up with using Allstar to command it. I don't know enough about Asterisk, but if someone would like to help figure this part out, please post. I have gotten the adapters to the stage where they are registered with the Allstar server as peers, but I don't know the specifics on how to make them virtual nodes and have the server initiate the interconnection.

    Before someone asks, I already tried using the DMK USB dongles for Allstar to tie the modems together- NO GO. There seems to be a timing sync issue between the dongles (even when run on the same PC) and the modems complain to no end. It's interesting because you can watch the complaint lights come and go and alternate between the two modems. They get false data and it just plain doesn't work.

    I forgot to take a picture of the modem/VOIP adapter combo running, but there's another success story below.

    Incidentally, I also have a 24/7 working link using 2x V.3225 modems along with 2x Telex IP-223 boxes. I run the modems in 4 wire lease mode in this scenario and the IP-223 provides the analog to IP conversion. This setup has actually been in service for a month without any hiccups. Here's a picture of the box working. Notice all the status lights (except the QM) on the V.3225 modem are lit. That means it's actively transporting the digital idle link check data and timing.


    Will that keep you guys happy for a while?
    Attached Images Attached Images
    Last edited by mizzotch; Aug 24, 2013 at 12:44 PM.


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    This is fantastic information.

    I'm already trying to acquire some of these parts.

    We also need to try and come up with a solution for those who do not have the V.24 daughterboard. There's really nothing special about that board; essentially it's just routing certain pins from the mating connector to the RJ-45 plug. There's another thread detailing this/discussion elsewhere on the board.

    If TRBO doesn't get its **** together soon, I'm heading back for AES-256/Quantars. This is definitely the way to roll.

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    Are you running this setup in mixed mode or P25 only?
    Quote Originally Posted by Bigfella237 View Post
    I've never really bothered 'playing' with ADP (it's like owning a Harley but still riding a tricycle)

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    Is this a pure digital link? Or double vocoded? What's the signaling protocol between the modem and the obahai?
    specializing in AES1056 encryption

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    Mars- It would be great if someone could layout a PC board for the V.24. They are so simple and can be made with a few MAX232 ICs as I recall. All you need is for the right connections to be made to the header and then out to the RJ-45.

    Okie, all my repeaters are mixed mode. This setup I describe however, is digital only. I use another completely separate link path to handle analog. With the VOIP adapter and V.3225 modem, you can only do digital. I figure most people have already got the analog part handled using another method. The pictures I posted which use a slightly different method with a Telex IP-223 box. IP-223 has two analog channels per box. I use the 'Radio 1' channel for analog and the 'Radio 2' channel for the modem data. Fore some perscpective, I'm using the MRTI port for the external analog controller interface (to the SCOM you see in the photos). The switching between digital and analog is very good if you implement it like I did. I have my PTT priority set to make the digital take over, even when analog is keyed. The Quantar instantly switches over and back.

    No, this is not double vocoded. It's V.24 data all the way. The stream is not altered. The link between the modem and obihai is POTS. To be considered double vocoding, I'd have to be using a DIU between, which I'm not. There is no DIU at all in the setup. In fact, I don't own one of those yet....it's on my wish list.

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    Yeah, what mizzotch just said. And all embedded signalling (RIDs, Soft IDs, KIDs, etc.) are all preserved in the data stream. This is the ONLY way to link P25. Anything else is welfare.

    What's the voice latency like? If I keyed up my radio and said "oh ****", how long before you hear it on your end? Are we talking about one second, under normal Internet latency? (50-200ms)

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    Since this seems to be based on the dialing Point A to Point B principle {as explained by the OP}.

    Q1: how long does the direct dial link stay up before having to reestablish a dial connection?
    Q2: Can you link more then two quantars or no?

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    Quote Originally Posted by Mars View Post
    Yeah, what mizzotch just said. And all embedded signalling (RIDs, Soft IDs, KIDs, etc.) are all preserved in the data stream. This is the ONLY way to link P25. Anything else is welfare.

    What's the voice latency like? If I keyed up my radio and said "oh ****", how long before you hear it on your end? Are we talking about one second, under normal Internet latency? (50-200ms)
    Funny you mention that Mars- With the latency, you definitely hear the tail end of your transmission when I routed through LA (with the 600+ms roundtrip). If you said "oh sh**" then unkeyed, you'd hear the sh** coming back. When I did the test, I had the link going from Astrotac to Quantar and played with the voice latency for a bit as I found it mildly amusing. If the two obihais are on the same LAN, you'll hear maybe the last syllable at most. Usually you hear just the brief moment of silence between when you stop speaking and unkey.

    123: The direct dial link will stay up for as long as the internet between the two obihais is constant. I ran overnight tests and when I came back in the morning, they were still solid.

    You could link more than two Quantars if you use an Astrotac with a modem & obihai for each channel. Remember, this is active bi-directional data handshaking we're doing here. It's a 1 to 1 setup. If you don't have an Astrotac, you're limited to linking two Quantars total using the RT/RT config.

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    Quote Originally Posted by mizzotch View Post
    Mars- It would be great if someone could layout a PC board for the V.24. They are so simple and can be made with a few MAX232 ICs as I recall. All you need is for the right connections to be made to the header and then out to the RJ-45.
    Ive made a semi-working protoboard for it, but I kinda want to know what is the exact circuit on the V.24 board before going to far, unfortunately this board does not seem to ever be included in service manuals, I have revisions -C and -E and neither have the V.24 board.

    EDIT: If someone has the chance - even without any schematic I can use high-resolution photographs of both sides of the board. If I can get something going I will post the Gerber files for people to order PCBs with or something.

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    kayfox: I still have a Quantar boxed up, with V.24 board installed. I'll pull it and take some high-res pics for you. Macro lens, proper lighting, etc. I'll see if I can get it done tomorrow. The Quantar isn't at my home QTH.

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    Quote Originally Posted by kayfox View Post
    Ive made a semi-working protoboard for it, but I kinda want to know what is the exact circuit on the V.24 board before going to far, unfortunately this board does not seem to ever be included in service manuals, I have revisions -C and -E and neither have the V.24 board.

    EDIT: If someone has the chance - even without any schematic I can use high-resolution photographs of both sides of the board. If I can get something going I will post the Gerber files for people to order PCBs with or something.

    Check your PM's.
    Last edited by iam4thapack; Aug 27, 2013 at 01:24 AM.

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    Excellent work guys!!

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    Mizzotch, Do you have piouts and settings? Excited!!!!
    Radio Referenced...Those who think they know it all are very annoying to those of use who do.

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    Here is the manual for the V.3225 modem and an Excel sheet with the pinouts for the interface cables. Now get to work!

    And, seriously, if there are any Asterisk experts out there, I could use your help.
    Attached Files Attached Files

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    Excellent interfacing chart. Could you please clarify which gender the DB25 connectors (cable side) need to be? Thanks

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    I have the circuit diagrams for the V.24 board and I'm working on a PCB.

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    Quote Originally Posted by Mars View Post
    Excellent interfacing chart. Could you please clarify which gender the DB25 connectors (cable side) need to be? Thanks
    You need MALE connectors on your cables. The modem data port and Quantar J14 MRTI are DB25 females.

    Also, you have to do some wildcard programming to make the RDstat output work on the telco interface. I found that the COS signal on the MRTI port will also indicate when receiving a P25 signal, so that's no good for mixed mode operation with external controller

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    Thanks! I'm going to make some cables up. Already have a pair of modems/VoIP adapters on the way.

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    Quote Originally Posted by mizzotch View Post
    You need MALE connectors on your cables. The modem data port and Quantar J14 MRTI are DB25 females.

    Also, you have to do some wildcard programming to make the RDstat output work on the telco interface. I found that the COS signal on the MRTI port will also indicate when receiving a P25 signal, so that's no good for mixed mode operation with external controller
    I found that problem also with the COS. I ended up using Relay 7 and set wildcard as (State and condition settings is State: RX PL DETECT) (Under action I have SET OUTPUT 7) (Under Inaction I have CLR OUTPUT 7). So this output RLY7 goes to the extrnal controller.

    I have access to probably 6 or 7 v.3225 and a couple v.3229 modem's. I want to play with this, but do not have a second quantar. Really want to play with some IP-223's there are 2 on ebay know for sale if any one is interested, they are not being sold by me, if so they would not be for sale, LOL


    Also on page 103 of PDF, Could you use Factory option set #3 for the VOIP device or Factory option set#4 if you use an IP-223? Would those factory settings be fine? depending of course which type of device you used weather OBi-100 or IP-223.

    I also assume you can use many of the telephone over IP units avaliable as long as they are unlocked from a provider, like vonage for example.
    Last edited by moetorola; Aug 29, 2013 at 01:22 AM.
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    I'm kind of amazed that running a MODEMs audio over a VoIP adaptor works!

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    Moe- I did basically the same thing you did for the wildcard programming. I also have the added condition of "RX QUAL MET"
    As for the factory defaults, you could be right. I just went through the settings myself to make sure things were right. Try it, you can't break it.

    I'm not sure about another VOIP adapter working. I just know it worked with this specific OBi-100. Maybe as long as it will support a fax, it might go. I think how well it handles jitter also has much to do with it working.

    MattSR- I was kind of surprised too.

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    mizzotch: Can the OBi-100s connect to each other without the Internet? Example: A simple private LAN (wireless) between both sites. From what I understand, if they do not have Internet access, they cannot direct connect each other as they're unable to access the Obitalk service.

    Thanks

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    Apparently, they can direct dial without Obitalk. There is quite a support community for these devices. See this thread here: http://www.obitalk.com/forum/index.php?topic=6363.0

    I've never tried the config they describe in the thread because I was wanting to go for the Asterisk server managed style connection. One of my eventual plans for our repeater net here is to have at least 4 Quantars full time linked and then have 1 Astrotac port dedicated to dynamic linking that could connect to a number of nodes anywhere on the 'net which are equipped with the V.3225 modem/OBI combo. I already have a private Allstar server at the main site and was going to use that to manage the switching of that Astrotac port. So, I'd basically have a true P25 linked node on Allstar.
    Last edited by mizzotch; Aug 29, 2013 at 10:28 AM.

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    I have regular pots at my site no internet as of yet. I am curious if you tried using regualr pots dialup with the v.3225 modems from site to site with out any OBi or ip-223.

    Could also be used as a backup to your IP-223 configurations if the LAN fails, and have fallback to POTS.
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    I tried POTS on a PBX for a short time just to verifiy the modems to work. It synced much quicker than the OBI. POTs is what these things were designed for after all. With these modems, you can test your connection without connecting V.24 data. If the modems connect and the LCD says 9600 ONLINE and the QM light is not on, then it's all good. The RD and TD lights should be off if there's nothing on the DB25. I noticed the RD light gives a slight flicker every now and then when only the modems are connected.

    MARS- I think the webserver locked out my IPs last night. I was editing my post, then I got an error message saying my post was fewer than 10 characters (which it definitely wasn't). Then I tried to go to advanced edit mode, got a 550 error, and now I cannot connect via my home or work computer. I'm on another machine now. Can you check on that? Thanks