[Asterisk-Users] The Minimum Cost of Setting up an Asterisk
Phone System?
Steven Critchfield
critch at basesys.com
Thu Nov 6 10:12:56 MST 2003
On Wed, 2003-11-05 at 15:03, Steve Murphy wrote:
> Everyone--
>
> Here's a cost analysis, rather crude and inspecific, of using Asterisk
> to implement a phone system. I'm really quite naive and new to all this,
> so I'd appreciate any corrections, tips, pointers, etc, from those in
> the community, who have far greater experience, knowledge, skill, etc.
> than I. Am I forgetting something important? Am I way off in my
> estimates?
>
>
> The Minimum Cost of setting up an Asterisk Phone system:
>
> Fundamental Building Blocks:
>
> 1. No more phones serviced than one computer can handle.
> 2. Computer = self-built or whatever, approx. $500
> 3. OS = Linux. $0
> 4. Phones.
> Cheap Touch-tone phones: $30 each (Estimate at what I can get
> at Walmart, quantity one purchases. No digital readout, no
> programmable features.
I originally picked up this AT&T 957 phone at Office Max for $30.
Currently the links from froogle show many people offering it for around
$30, and one for $20. (http://tinyurl.com/twyi) Speaker phone, CallerID,
callerid memory, and directory dialing.
> Voip Phones $250 estimated per-phone average cost. Realize that
> costs can vary widely here!
> 5. Channel Banks. Looking at what's available on Ebay, I estimate you
> should be able to pick up a fully loaded, 24-channel FXS/FXO bank for
> $650 average. Low = $200 High = $4500. I have no way of telling
> which channel banks are compatible with asterisk. Assume that they
> are.
> 6. Digium cards: FXO card = about $100. FXS card = $125.
> 4 port FXS=$300. Prices approx. See their web site
> for exact prices.
> quad span T1 (96 lines total) $1500
> Single span T1 (24 lines) $500
> 7. Wiring. Cost of Wiring is not calculated. Assume that the premises
> is wired, with patch panels, closets, etc., already in place.
> 8. UPS, power supplies, etc: Not specifically included in the estimates.
>
> 9. Used equipment can be cheaper, but: if you need a lot, you may not
> necessarily be able to wait around for everything you need to show up on
> ebay. And what you get may not be what you wanted, etc.
>
>
> Scenarios:
> 2x8 system:
> Computer: $500
> 2 FXO : $200
> 2 4-FXS : $600
> 8 phones: $240
> --------------
> Total: : $1540 cost/phone = $192.25
This option may not work in one PC as you have more than 2 Zapata cards.
You will find it difficult to make the cards sit on their own IRQ, then
you will deal with 4 x 1000 interupts a second on the machine. Not to
mention you will be at the end of your potential expansion in a single
machine. You would find it almost the same price to switch to a T100P
and a channel bank with FXO and FXS ports. This would alleviate
headaches of IRQs, and future expansion is probably just a matter of
plugging in more phones.
> 96 line system ( FXS/FXO mix 88/8)
> Computer : $ 500
> QspanT1 : $1500
> 4 ChanBks: $2600
> 88 phones: $2640
> ----------------
> Total: : $7240 cost/phone = $82.27
>
> 192 line system (FXS/FXO mix 176/16)
> Computer : $ 500
> 2 QspT1 : $3000
> 8 ChanBks: $5200
> 176phones: $5280
> ----------------
> Total: : $13980 cost/phone = $79.43
I have a small problem with the above 2 examples in that they assume you
can get by with 11 users to a phone line. I think this is not normally
possible unless you are dealing as a telco serving residential lines
that don't have dialup internet users. I also don't feel that a $500
computer can sustain 8 T1s of traffic today. Maybe in a year the prices
will have fallen enough so that a $500 PC is adequate.
I suspect the examples above should be stated more likely as a
96 line system (FXS/FXO mix 72/T1 or PRI 3 users per line)
Computer : $ 500
QspanT1 : $1500
3 ChanBks : $1950
72 Phones : $2160
-----------------
Total: : $6110 costs/phone = $ 84.86
192 line system (FXS/FXO mix 168/T1 or PRI ~7 users per line)
Computer : $1000 Needs more power
2 QspT1 : $3000
7 ChanBks : $4550
168 phones: $5040
-----------------
Total: :$13590 costs/phone = $80.89
These also have the potential to save money month after month by having
subscribed to a T1 or PRI link and having more phone lines available for
the employees.
> Voip 24 x 192 Phones, using gnophone on existing comps & network:
> Computer : $ 500
> 1spanT1 : $ 500
> 1 ChanBnk: $ 650
> 192 gnoph: $ 0
> ----------------
> Total: : $1650 cost/phone = $10.18
>
> Voip 24 x 192 phones, using Voip Phones:
> Computer : $ 500
> 1spanT1 : $ 500
> 1 ChanBnk: $ 650
> 192 gnoph: $48000
> switch/hubs: $ ?
> ----------------
> Total: : $49650+ cost/phone = $258.59+
These also have problems. At the point you put 24 lines in a system, you
really should be getting T1 or PRI service. When you do that you remove
the channel bank from each of those examples above.
24x192 gnophones drops to a total of $1000, and cost/phone of $5.20
24x192 hardphones drops to $49000 with a cost/phone at $255.20
As has been mentioned you could get some other models of phones that go
for less than $250 each. Not to mention at the 192 mark there will be
some nice price point drops.
> Cheap $30 phones are an option, but you will not get:
> Intercom capability
So far this isn't an option with any of the asterisk systems unless you
use an overhead/loudspeaker solution.
> Message waiting capability
> CallerID type stuff.
Both of these are possible, Note features listed above regarding the ATT
957.
> Gnophones may or may not provide intercom, I haven't gotten that far as
> to find out.
I think the closest it supports would be an autoanswer.
> VOIP phones are expensive, but MAY provide intercom, and other fancy
> feature, if Asterisk will allow them. It's not clear yet to me that
> Asterisk will allow intercom. Looks like you might get message waiting.
So far it isn't a question of whether or not asterisk will let you, but
if the VoIP protocol supports this function. So far I think we have
determined that it isn't supported but in th SCCP protocol. Maybe this
should be looked at for IAX2 inclusion and for when someone implements a
full on IAX2 hardphone. I'm betting it wouldn't be too hard to embed the
IAXIE(sp?) into a phone like the ATT 957 and have a relay trip the
speaker phone button when you wanted intercom.
--
Steven Critchfield <critch at basesys.com>
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