[c-nsp] analog to digital

[Jonathan Charles]

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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