ContactID over NBN

[Unbeliever]

Has anyone had any experience with sending ContactID over NBN? I'm led to believe that the NBN transmits DTMF (ContactID) out of band as data and reconstructs it at the other end, which is fine for human keypresses, but can mangle the much faster ContactID DTMF digits.

I've had a bit of a look at the NBN config files, but there doesn't seem to any setting for in-band vs. OOB DTMF.

Has anyone experienced problems with this?

Are SIA and IRFast (being modem formats) better?

Are the medical alarm guys having problems?

Thanks,
Unbeliever.

[Drift]

There are a number of challenges with transmission of Contact ID, or any of the security DTMF formats over VoIP connections. On the surface, it should work but it can't be guaranteed. The primary reason being the varing implimentation of the G.711 codec by various equipment manufacturers, then the possibility that the RSPs will apply futher compression to the signal in order to reduce bandwidth. Receivers are pretty fussy about what they'll accept and some panels can be equally as fussy about the handshake and kiss off. The second issue is that of latency. Both the panel and the control rooms receiver are expecting a sequence of singals to occur within a given time frame based on a trigger from the other side. IE: Panel dials receiver, receiver answers and responds with handshake, panel transmits first signal, receiver acknowlages with kissoff, panel transmits subsequent signal, receiver acknowlages etc. If the timing is out of the parameters that either equipment is expecting, again it's possible that nothing will be received.

Aside from the transmission issues, there are more potential points of failure with NBN connected premises than with PSTN communications. There is no guarantee of comms in the event of power failure as the consumer equipment, at least for now, has an optional backup battery. Even if there is a battery, reporting of the status of that battery is limited to the device it's self and able to be disabled by pressing a button. Consumers being consumers, there is the likelyhood that it'll be ignored. The other issue is that there is no requirement for that equipment to be installed inside the protected area. Client's can request this, but it's no guarantee and in some case's client's will have to pay more to have the device installed in a location of their choosing.

The best option at the moment to ensure continued operation of the security system/medical alert system using Contact ID over PSTN, is to install something along the lines of the UC-351, enabling an IP and 3G communication path.

As a bit of histroy, I've tried sending contact ID over existing VoIP services when Naked DSL started increasing in popularity. The results were mixed based on what I spoke about above. Some worked, some didn't. Some ISPs were better than others, some modems better than others and some panels better than others. Having said that, what worked in one site, didn't necessarily work in another. A firmware upgrade of a modem, panel, DSLAM etc and things could go pear shaped. Things will be no different under the NBN.

[downunderdan]

Even if you get it working, there is a good chance it may stop working all of a sudden with no warning. There is no guarantee of service and security providers should act on this basis and move toward an IP solution rather than a band-aid.

Google for "ASIAL" and "NBN". They've been doing a lot of work in this area.