[c-nsp] analog to digital

[Jonathan Charles]

OK, first off, how many IP phones? The 1760 can only support 24 IP phones.

Second, you need to match up the analog port channels with DSPs.

Generally, as a soft rule of thumb (no hard and fast rules for DSP
calculations), if you want to terminate a voice call (from the PSTN), you
need one PVDM channel.

PVDMs are packaged by the amount of channels. e.g. a PVDM-4 has four
channels and can generally terminate 4 voice calls.

For other uses (transcoding, conferencing, etc.) you need to look at DSP
counts and that is probably more than you are looking for (just as a side
note, the Cisco 1760 can provide conferencing resources (if you have the
DSPs) for ONE conference call of up to six participants).

You are also going to run into a software problem, you need to get a voice
load that has CallManager Express and is licensed as such.

>From there, you can load all the files to the router and admin this from the
web.

But you need to get your hardware house in order first.



Jonathan



On 12/21/06, George Sobhi <gsobhi at nileonebrokers.com> wrote:
>
>  Dear all,
>
> I have already a 1760 not 1760-V and am a newbie of this field and the
> issue as follows:
>
> My company will contract for a service that provider will provide us an
> analog line from PSTN and I need all IP phones use this analog line.
>
>
>
> Jonathan, your email was very helpful but is there an addition for the
> case above?
>
>
>  ------------------------------
>
> *From:* Jonathan Charles [mailto:jonvoip at gmail.com]
> *Sent:* Wednesday, December 20, 2006 7:05 PM
> *To:* Voll, Scott
> *Cc:* George Sobhi; cisco-nsp at puck.nether.net
> *Subject:* Re: [c-nsp] analog to digital
>
>
>
> Yeah, but you end up paying a LOT more if you buy a 1760-V, versus a
> stripped 1760 and then buy the PVDMs on Ebay.
>
>
>
> Jonathan
>
> On 12/20/06, *Voll, Scott *<Scott.Voll at wesd.org> wrote:
>
> Was this a 1760-V?  the V model had DSPs stock.
>
> Scott
>
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net
> [mailto:cisco-nsp-bounces at puck.nether.net ] On Behalf Of Jonathan Charles
> Sent: Wednesday, December 20, 2006 5:59 AM
> To: George Sobhi
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] analog to digital
>
> Here's the thing.
>
> FXO ports are expecting to receive dial-tone, FXS provide it.
>
> So, the line from telco plugs into an FXO and a phone plugs into an FXS
> port.
>
> For any of these to be recognized by the router you are going to need
> DSPs
> (in the form of PVDMs).
>
> So, it really depends on what you want to do.
>
> If you have IP phones, then you just need FXO ports (you can get a
> VIC-2FXO
> card for a 1760 on Ebay for about $100), and you can get PVDMs (a
> PVDM-8,
> will cover you pretty well for analog on a 1760, for about $100).
>
> The DSPs turn the analog waveform and sample (eight thousand times a
> second,
> generally) and put that waveform into IP packets (usually with 20ms of
> voice
> per packet) via an audio codec (usually G.711 or G729a).
>
> Without DSPs, two things happen.
>
> First your router will not see the voice ports (not even know they are
> in
> the box), second, you wouldn't be able to packetize voice without them.
> So,
> they are necessary.
>
> Some hardware modules have DSPs on them (the NM-HDV for example), but
> most
> do not.
>
> The working assumption is that that you will scale your DSPs to meet
> your
> needs (they do more than JUST packetize analog audio, they can also
> provide
> transcoding services, conferencing, and act as a media termination point
> (for putting people on hold).
>
>
>
> Jonathan
>
>
> On 12/20/06, George Sobhi < gsobhi at nileonebrokers.com> wrote:
> >
> >  Dear Jonathan,
> >
> > Are FXO and DSP different? And if I purchased FXO do I need to
> purchase
> > FXS also???
> >
> > Thanks & regards
> >
> >
> >  ------------------------------
> >
> > *From:* Jonathan Charles [mailto:jonvoip at gmail.com]
> > *Sent:* Wednesday, December 20, 2006 3:49 PM
> > *To:* George Sobhi
> > *Cc:* Kevin Graham; cisco-nsp at puck.nether.net
> > *Subject:* Re: [c-nsp] analog to digital
> >
> >
> >
> > Well, one way or another, you are going to need ports to plug the
> lines
> > into and you are going to need DSPs, there really isn't a way around
> it.
> >
> >
> >
> > Jonathan
> >
> > On 12/20/06, *George Sobhi* < gsobhi at nileonebrokers.com> wrote:
> >
> > Dear Kevin,
> > Sorry I mistyped my router is 1760 and if there is a way to do that
> > without
> > purchasing any hardware??
> > Thanx and regards
> > -----Original Message-----
> > From: Kevin Graham [mailto: mahargk at gmail.com]
> > Sent: Tuesday, December 19, 2006 6:40 PM
> > To: George Sobhi
> > Cc: cisco-nsp at puck.nether.net
> > Subject: Re: [c-nsp] analog to digital
> >
> > On 12/19/06, George Sobhi < gsobhi at nileonebrokers.com> wrote:
> > >
> > > How can I figure the PSTN analog line to 2700 Cisco router?
> >
> > Atleast one of those numbers is wrong -- 2700 doesn't exist, perhaps
> > one of 1700, 2600, 2800, 3700? Either way, what you're looking for is
> > an FXO interface; with that, and the right model number the
> > appropriate part should be easy to chase down on CCO.
> >
> > _______________________________________________
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> >
> >
> >
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