Re: Should legacy technologies be allowed to remain forever? [Telecom]

Having read the recent posts about people being cut off copper for fiber,

> and also being compelled to switch to Digital TV, it occurs to me that the > underlying question should be is it really fair to retain - essentially > ancient - technologies?

Is the current 48V DC telephone set obsolete? It's using the same signalling protocol of "common battery" switchboards of nearly 100 years ago.

Should we all have telephone sets that are VOIP compatible--is that the new protocol? Do such sets need their own power?

Reply to
hancock4
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Cisco 7960 (and similar) VoIP devices "prefer" PoE (Power over Ethernet), but they can operate with external power supplies (e.g., "wall warts") on LANs without PoE-capable switches.

Reply to
Thad Floryan

All good points, but for a true evaluation perhaps we have to remove our thinking of how the old technologies provide the service (phone service powered from a central point, terminal line powered) and think along the lines of the actual service to be provided - a usable voice communication device that meets our requirements for reliability/cost etc?

It can be difficult to "think outside the box" for these things, especially when they have been with (most of) us for all our lives, and even more so if we are involved in a professional level, but perhaps it may be worth while to let the discussion rip! ;-)

Reply to
David Clayton

Just on these Ethernet connected devices, does anyone know if the major power use of these things is just keeping a valid Ethernet link going?

If we ever want to get wired non-PSTN devices close to the level of reliability we currently have with PSTN devices, then perhaps someone should be working on a way to reduce their power use to the level of cellphone handsets.

Reply to
David Clayton

Cisco developed the PoE concept in 2000 for VoIP telephony. I've setup several asterisk phone systems using Cisco 7960 and Polycom IP4000 devices. The 7960 use PoE and the Polycoms have an external power module.

PoE is 48 volts DC, and many/most/all PoE telephony devices could consume up to 15+ Watts of power.

Devices such as the Cisco 7960 and Polycom IP4000 are, for all intents and purposes, computers with integrated RAM, FLASH, LCD display, Ethernet, audio circuitry, etc. and are intended to operate 24/7. When there's a power failure they get their IP address via DHCP followed by a tftp boot for the operating system.

Looking at this Cisco document:

there are power issues with PoE Ethernet switches. Depending on the standard, the phones will use up to 15.4 Watts but negotiation can drop usage to 7 W. Some Cisco switches with 48 ports and only 370W power capability can be quite problematic and unable to support 48 phones.

If you have specific questions about the 7960, IP4000 and/or asterisk, I'd be happy to answer from my notes and memory, though it's been slightly over a year since I've "played" with an asterisk VoIP system and the devices. My notes do span several CDs and include literally all the docs and manuals.

Two new systems I have arriving soon are complete, full-featured Linux "boxes" which are about the size of a wall-wart power supply and consume less than 5 W, have GiGE, USB, and other features. Glance at these pictures:

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Product details can be seen here:

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Another low-power and amazingly low-priced possibility is this:

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"Green" computing is clearly here. :-)

Reply to
Thad Floryan

Hi Thad,

Asterisk has always interested me, but I'm not up to speed on available hardware products.

Could you recommend some very low-cost VoIP devices that would convert the Asterisk VoIP to POTS, so common 2500 telsets could be used?

Perhaps even VoIP lines into 1A1 and 1A2 KTS as well?

TIA.

Reply to
John F. Morse

.......

I suspected such, where I work I have a cabinet with 3 Cisco 24 port switches providing PoE on most ports and these puppies suck a lot of juice from my UPS (and generate a lot of heat themselves).

Compared the the power an on-hook POTS set (or possibly even a proprietary digital handset) consumes we certainly have taken a step back in the amount of power a terminal telephony device now consumes.

I wonder if the extra power these PoE devices (and their connecting equipment) consume is offset by the reduced power consumption of their switching equipment (compared to a PBX)? It would be interesting to see if their are any studies on this given the push to reduce overall energy consumption.

Thanks, the info you have already provided is most enlightening.

.......

Let's hope so, it would be a shame if our embrace of newer comms technologies significantly increased overall energy use - especially when we are not actually using the bloody things!

Reply to
David Clayton

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Both the Sheeva and the Marvell devices look very intriguing!

The Marvell, I see, has a VGA output port, and can, I'd imagine, serve as CPU for a full linux system with USB kb & mouse and VGA monitor.

But the Sheeva? Or is that just a "headless" server?

Thanks, Thad, for bringing these to our attention here! And cheers,

-- tlvp

Reply to
tlvp

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There is also another tiny "Box" PC device that has been around for a while:

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Reply to
David Clayton

In theory, any "analog telephone adapter" (ATA) for VoIP should work. At my last client site, they already had an older asterisk running on Fedora Core 2 (yeah, I know it's ancient) which I upgraded and added the Polycom IP4000 conference room phones, corrected their dialing plans, and updated the firmware for the Cisco 7960 phones. They had several Sipura SPA-2000 ATAs for the FAX machines, but they weren't functioning reliably and I never had an opportunity to determine why (and correct it) since the company went belly-up.

The Sipura device is touted for connecting standard telephones and FAX machines to IP-based data networks, and it should have worked. Whoever had "messed" with that asterisk system before me had hosed it to the point their VP Engineering said it was impossible to make the Polycom IP4000 (they had one) work, but I proved otherwise and bought/installed several more IP4000s.

equipment like facsimile, voicemail, PBX/KTS and interactive voice response systems". Hmmm,

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now redirects to Cisco here:

and apparently the SPA-2000 is now a discontinued product. If you want to see its data sheet:

A Google search on "VoIP analog telephone adapter" returns a number of useful hits for ATA products whose pricing seems to begin around US$50. Sorry I cannot offer any specific recommendations.

Reply to
Thad Floryan

Correct! For US$200 ($250 with case), fanless, physically small and operating using minimal power, it's quite a deal.

Right, a headless server. I intend using one of mine for DHCP, tftp booting, local DNS, syslogging, email, weather station data capture, and possibly NTP (time) replacing an old desktop which uses too much power running 24/7. The other will be used for product development.

You're welcome! I hope these and similar other ones give you some ideas! These should be capable of running asterisk, too; something to try.

:-)

Reply to
Thad Floryan

Thanks for that pointer, David. And cheers, -- tlvp

Reply to
tlvp

Thanks, Thad, for the further details. Cheers, -- tlvp

Reply to
tlvp

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