TELECOM Digest OnLine - Sorted: Re: VoIP

Re: VoIP

Robert Bonomi (
Thu, 28 Apr 2005 02:58:08 -0000

In article <>, Choreboy
<> wrote:

> For several months I've been getting calls with spoofed Caller IDs. I
> understand spoofing requires either VoIP or a PBX system with DSL.

> Can anybody with cable internet access and suitable software make VoIP
> calls?

> The other day I received a wrong-number call from an exchange belonging
> to Level 3 Communications. Among other services, they offer residential
> VoIP services through wholesalers such as ISPs and cable operators. I'm
> confused. Does a consumer need these services to use VoIP?

> [TELECOM Digest Editor's Note: I don't think either 'VOIP' or 'PBX system'
> have anything to do with it. If I understand correctly what I have
> read here in the Digest, it requires a 'PRI' type thing; that is, a
> multi-channel set of lines going to DID, or Direct Inward Dialing,

Would you believe "DOD" -- direct *OUTWARD* dial?

"DID" trunks handle incoming calls only.
"DOD" trunks handle outgoing calls only.
"DID/DOD" trunks handle both.

Caller-id data _origination_ occurs only for outgoing calls.

> which would, I guess, be similar to a PBX arrangement.

Some sort of a 'switch', usually a PBX-equivalent, is required to
handle DID / DOD trunks.

Then there are the "big boys" -- who have SS7-compatible switches,
which are a C.O.-equivalent, rather than PBX-equivalent, device.

> Companies who have those lines _can_ set the caller ID to be
> whatever is appropriate in their instance.

Sometimes the telco 'filters' what CID data the company can send,
sometimes not. When "not", an unscrupulous company can set the ID
info to _anything_.

Unfortunately, the "lowest-priced" PRI providers are the ones least
likely to do filtering, *and* are the ones that said unscrupulous
companies are most likely to use.

> I suspect the fact that the ID shown was that
> company may have been just coincidental. You do need either cable
> internet or DSL to use VOIP; regular 'dialup' lines are just not wide
> enough or fast enough to do VOIP. But other than having DSL or cable,
> VOIP takes nothing especially fancy; just an adapter box from the
> place where you get the VOIP service and any regular telephone
> instrument will do the job. And if you planned on totally getting
> rid of your landline phone taking VOIP instead, that is generally
> not possible with DSL, since most telcos will not give stand-alone
> DSL.

Unless you buy SDSL service, which is _always_ delivered on it's own

Unless you get your DSL from MCI, Covad, or New Edge Networks -- or a
'reseller' of any of those carriers -- all of whom offer
dedicated-pair ADSL.

Unless Qwest is your ILEC.

[TELECOM Digest Editor's Note: But I _defy you_ to pick up your phone
right now and talk to the first service rep who answers and order SDSL
service. They will not know what you are talking about; probably no
one in the vicinity will know. And if you _do_ order it satisfactorily
from MCI, Covad, New Edge or others, then God bless you; it will be
extraordinarily expensive and if your intent was to save money by
going with VOIP instead of landline, you've completely killed that
plan. In essence -- in real life practice and experience -- you cannot
get stand alone DSL (and pay your VOIP bill each month on top of that)
in any reasonable cost-effective way. After arguing with the service
reps for some period of time on the matter, you will decide cable is a
better and less expensive way to go. PAT]

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