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Data over IPTel

Okay, so the title was confusing, but...

This is the desired result, does anyone have a proven method.

S1 is a server at NOC1, S2 is a server at SITE1. SITE1 has IP Telephony solutions built into the network. SITE1 also has a VG200 routing telephony calls out of the building via a local telco. If the data link between NOC1 and SITE1 is lost, there should be a way for S2 to initiate a data call (like a modem) through the VG200 to an incoming modem on S1 at NOC1. Assume there are no open analog ports at SITE1 and that there is NOT an option to put an analog modem into S2. I would think that somehting could be done similar to SoftPhone, but for data... where SoftPhone initiates voice communications from a desktop PC out a VG200 somewhere, why could a data connection not be made using the same/a similar method?

Community Member

Re: Data over IPTel

This can only be acomplished with a modem.

In order for the data to transverse the PSTN network, it must be in analog format. The modem converts a digital signal into an analog format to be reconverted into digital format at the recieving end.

The voice gateway, on the other hand, does the opposite. It takes analog signal (namely voice) and converts into a digital signal to be converted back into analog at the far end.

While the 2 functions may seem similar, the actual process is very different and the same processor cannot do both. On some routers it is possible in install digital modem, but I do not beleive the VG200 supports these. I do know that the as5000 series and the 3660 series do, however.

Community Member

Re: Data over IPTel

That doesn't fit with my understanding of IPTel... the Voice Gateway takes digital voice as IP packets (from the IP Phone/CCM) and translates it into an analog stream to be sent to the telco. Or do telcos always require digital? Do standard PBXs send out digital data?

Community Member

Re: Data over IPTel

You misunderstand me. The data over PSTN (using modems) tunnels digital information through an analog medium. The IPTel system tunnels analog information through a digital medium.

The key is that in each case, the end devices are only designed to accept general information in one format, convert it to an intermediate format that can be understood by the far end, and the far end converts it back.

In the case of IPTel, the IP phone converts the sound (actually, only the subset of the sound that the majority of humans can hear) and send the converted signal to either another IP Phone or a gateway where it is converted back into an analog signal.

In a modem, the modem accepts data in a serial format (i.e. no IP) converts it into an analog format that only another modem can intepret and transmits it over the wire.

The gateway or IP phone cannot convert general data into sound and the modem cannot convert general sound into data. That is how they are different.

Community Member

Re: Data over IPTel

If I read this correctly, you want the VG200 to be the backup data router and perform some sort of DDR out it's current telco connection, right?

First, tell me a bit more about the VG200 and it's telco connection. ISDN BRI? PRI?

Second, detail more about the data link between NOC1 & SITE1 and the routing that is taking place now. There are always options, like Dial on Demand routing, or perhaps peeling off a channel of a PRI to an ISDN modem on the data router...

Need more info.

And, BTW, a VoIP PBX doesn't always have to send voice calls to the PSTN as digital, and likewise, a TDM based system doesn't mean all PSTN calls must be analog. The PBX's PSTN connection is not determined by the transport used for sending conversation.



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