Telephone Interface will not work with answering machines

Discussion in 'C-Bus Wired Hardware' started by PSC, Nov 21, 2004.

  1. PSC

    PSC

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    Has anyone hooked up a CBTI with an answering machine and have to two co-exist successfully on the same line?

    We have found that there is a problem when we connecting a stock standard Panasonic answering machine to the CBTI.

    Problem -

    When the answering machine answers the call the CBTI seems to grab the line even though the "line grab" LED does NOT light up. It then continues to hold the line for 60sec. So, if you try to call back within that time all you get is an engaged tone.

    This setup was tested at two separate sites -

    Site 1. The CBTI grabbed the line only after the answering machine tone was heard.

    Additional information regarding site 1 -
    Dial in - answering machine answers ? cannot leave message ? cannot dial back for 1 min. (Primary)

    Dial in - answering machine answers ? cannot leave message ? press 5 for Cbus ? Cbus answers & works ? hang-up - can dial back in immediately. (Primary)

    Disconnect power to CBTI ? dial-in - answering machine answers ? can leave message ? can dial back in immediately. (Primary)

    Re-connected power to CBTI ? dial-in - answering machine answers ? can leave message ? can dial back in immediately. Only works first call in after disconnection. (Primary)



    Site 2. The CBTI grabbed the line before the message was complete. Disconnected the Cbus cable, left the power & telephone lines connected - answering machine works fine.

    A number of different configurations were tested; including removing all other telephone devices from the system etc.

    Don & Ryan (CIS), I have spoken to you guys at length regarding this problem - can you please sort it...
     
    PSC, Nov 21, 2004
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  2. PSC

    Richo

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    I see you have disabled the CBTI from answering any incoming call (both modes) when using an Answering Machine, that's good. And I assume when you say that you press 5 to access CBUS, that 5 is your local ACCESS CODE? What is the Answering Machines programmed behaviour when you press 5, you need to ensure that there isn't a conflict between the 2. Have you tried different access codes (say the default of #3#)

    Did you try the Answering Machine on the Secondary Phone Port of the CBTI?

    During "abnormal" disconnects (Whilst online to CBTI you hang up without using the hang up menu option) it can take a varying amount of time to detect the hang up, and thus block calls that come straight in. But it shouldn't take a full minute.

    I assume the phone line is a direct Telstra exchange line and not run through some sort of PABX?

    I'm doing some checking of the CBTI at the moment as Version 1.13 of TICA is being prepped for release (no firmware changes though, so the behaviour will be no different). I'll see what I can do to replicate the behaviour above.
     
    Last edited by a moderator: Nov 22, 2004
    Richo, Nov 22, 2004
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  3. PSC

    PSC

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    I have tried several codes, this was our first thought - maybe the answering machine doesn't like our codes. So we purchased another answering machine; guess what? same problem.

    Yes, originally we had it connected to the secondary as instructed. During our trial and error testing we connected it to the primary port - same result.

    An abnormal disconnect would mean that we have connected in the first place? We don't even have to try to disconnect for the CBTI to hold the line for 60sec.

    No PABX's.

    Buy a Panasonic answering machine from Bing Lee (or some other Panasonic dealer) and test it out for yourself...
     
    PSC, Nov 22, 2004
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  4. PSC

    Richo

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    Thanks for the extra info.

    I am waiting for Don and Ryan to get back in to the office, they had today off as they did training over the weekend. They know where the test equipment is (i.e. answering machine). They should be back tommorrow. Not sure the brand yet.

    Will do some testing and contact you if I need more info, I have you number :)
     
    Richo, Nov 22, 2004
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  5. PSC

    Richo

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    OK.... I'm getting somewhere in my investigations on this one... more info to follow soon.

    Hang in there.
     
    Richo, Nov 24, 2004
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  6. PSC

    Bad Boy Bubby

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    pcs you might just have easily said that you had a problem fitting a panasonic answering machine to a stock standard c-bus phone interface have you asked panasonic why there answering machine doesnt work with c-bus?
     
    Bad Boy Bubby, Nov 26, 2004
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  7. PSC

    PSC

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    This is not the first third party device that does not work with the CBTI.

    Clipsal have a register of mobile phones that are incompatible with the CBTI, including my Nokia 6600.

    So bearing in mind that Panasonic have been around and involved in the telecommunications field for a litter longer than Clipsal; and are less likely to release a product without thorough testing (unlike Clipsal), I would strongly suggest the problem is with Clipsal and NOT Panasonic!

    But thanks for the tip...
     
    PSC, Nov 26, 2004
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    Duncan

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    I seem to recall my Panasonic Cordless Phone/Answering Machine dropping my modem out every 25mins back in about 1999, oh well.. no sleep lost, I bought a different brand and it worked.

    Its common knowledge that getting a variety of devices working on the same telephone line all trying to offer some form of value added loop or DTMF detection is rarely straightforward, you often end up mixing and matching devices until a compatible mix is found.

    Its nothing to do with a lack of testing.
     
    Duncan, Nov 26, 2004
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  9. PSC

    PSC

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    Could you please tell me what brands / models of answering machines you tested it on?
     
    PSC, Nov 26, 2004
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  10. PSC

    Duncan

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    No, I write software, I dont test hardware.
     
    Duncan, Nov 26, 2004
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  11. PSC

    PSC

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    If Clipsal product testing was carried out on interfacing the CBTI with answering machines; surely someone in tech support would have informed me by now of a brand / model that does work.

    My guess is that Clipsal has not carried out testing the CBTI with answering machines...

    Is this another product that CIS has been released, awaiting the CIS integrators to pin point all the bugs?

    Clipsal is starting to sound like it's a division of Microsoft more and more each day.
     
    PSC, Nov 26, 2004
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    Duncan

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    Peter,

    I know for a fact it was tested in various scenarios.. alarms, faxes, answering machines, ADSL.. I dont have the specifics to hand.. but they wouldnt be much use to you as these sort of issues are often further dependent on characteristics of the individual telephone lines and exchanges and presence of things like Pair Gain Systems and then the actual method of connection overlaid on top as well as the actual configuration of the 'other' consumer device which is often capable of operating in many different modes.. This is why you are called an "Integrator" and not an "Installer" :)
     
    Duncan, Nov 26, 2004
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  13. PSC

    PSC

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    We are both actually...
     
    PSC, Nov 26, 2004
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    ashleigh Moderator

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    The telephone interface uses a modem IC from a well known manufacturer to do all of the telephone related functions. Its ability to do magical things is limited by the modem IC's capabilities.

    This has the advantage that you can use it as a modem for dial-in update / commissioning access to a site, using the "data mode". It also means that its limited by the abilities of the modem IC.

    It is fairly well known that trying to do lots of functions on a single phone line is a difficult and error-prone business. Factors that can make a difference include type of exchange, distance from exchange, condition of wiring between subscriber and exchange, and the nature of the devices attached to the line.

    The issue with some mobile phones is bouncing back and forth with the modem IC manufacturer. At this stage it looks like some models of mobile phones are the culprit, but there is no quick and simple resolution to this one. Mobile phones DO NOT use DTMF to do their signalling of phone numbers and so on to the base station - its all done with clever digital stuff. When the call has been established, the mobile phones then switch the keyboard to generate DTMF. It *looks* like the DTMF generation is a bit cheap and nasty - falling outside the frequency and/or amplitude limits established by Bell Labs many years ago :mad: Follow up of this is difficult and time consuming, with lots of complex measurements that need to be made locally and sent to the USA for analysis.

    The issue with answering machines appears to be related to some of those machines that stop the answer / record process when you pick up the (nearby) phone handset. Again, there is no simple change possible in the CBTI, though some further measurements and experiments might reveal more. At this stage, options on this one appear to be:

    . choose an answering machine where you can disable the option to automatically cease recording when phone is picked up (OK if the answering machine is near the phone - just manually press the stop button when you pick up the phone)

    . put in a second phone line :mad:

    Further investigation will reveal more, but there won't be an instant/quick fix.
     
    ashleigh, Nov 27, 2004
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    Frank Mc Alinden

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    Hi Peter
    I wouldnt say its a lack of testing on Clipsals behalf is the reason why the telephone interface works , or even brand types...I use Homevision which also has a telephone interface and some functions of the interface wont work in some installations , ithink the main cause with the Homevision telephone interface is line noise ...In my installation for instance Homevision cant detect when another phone takes the line off hook....
    Frank
     
    Frank Mc Alinden, Nov 27, 2004
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    ashleigh Moderator

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    Detecting line going off hook is one of the biggest pains in the universe :)
     
    ashleigh, Nov 27, 2004
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    Richo

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    Phew...hasn't this thread been busy over the weekend.

    Peter, as Ashliegh mentioned the problem between the answering machine and the CBTI is to do with the answering machine deciding to hang up when it detects a local pickup. The CBTI does a local pickup to sniff the DTMF tones to look for the access code.

    There is no fault with either unit, it's just a behaviour mismatch. The immediate answer is to use an answering machine that doesn't hangup under this circumstance.

    I can't understand the tone of you recent posts. I spent a good deal of time researching the problem the moment you posted to the forums. I even pulled the very expensive Exchange Simulator out our production facility to create a clean room test environment and experimented with work arounds to try and resolve the issue. I would have thought this was all a good thing. I especially spent extra time on this because of the very valuable and constructive feedback you have provide during the development on the C-Bus Toolkit.

    I have been waiting on final approval to post a information notice on this issue, and hence the slight delay in responding on the forum. Hopefully this will be approved soon as I'm waiting on the exact text prior to releasing the next verison of Tica (Which has a had a bit of time spent on it to resolve communication issues with USB <-> Serial adapters and Laptop serial ports).
     
    Richo, Nov 28, 2004
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    Bad Boy Bubby

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    try ity first

    I think we could all take a leaf out of Rossco's book (different thread re effect of ellectric fence on C-bus comms) and try this stuff out before installing. I would have thought it prudent to test out first any set up that used equipment from two or more different manufacturers rather than assume that it will work assume = ass u me.
     
    Bad Boy Bubby, Dec 1, 2004
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  19. PSC

    PSC

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    Richo,

    Do you have any updates re the CBTI / answering machine incompatibility?
     
    PSC, Dec 7, 2004
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  20. PSC

    Richo

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    Hi Peter,

    Currently the only solution to having a CBTI and an Answering Machine on the same line is to use an answering machine that doesn't hang-up when it detects a local pickup.

    We are researching the viability of changing the behaviour of the CBTI, but that will be a lengthly process and there will be no short term modification available.
     
    Richo, Dec 7, 2004
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