[Asterisk-Users] Integrating with existing analog PBX

2005-09-11 Thread Martin Allen
Hi.

Am new to this concept but have been requested to add VOIP capability to a 
small office phone system.

They currently have 4 standard analog lines running into a PBX feeding 16 
phones, with all the usual features,
call transfer
call hold
internal calls
etc.

would the following seem reasonable ?

asterisk server:- ( what specs )

cat5  broadband (VOIP)
4 FXO's for incoming PSTN lines ( TDM04B ? )

4 FXS's for output to existing analog PBX ( TDM40B ? )

Leaving the existing infrastructure as is but inserting asterisk box as a 
filter between internal system  external PSTN lines so presumably a user 
could add a prefix to a number to have asterisk route the call via VOIP or no 
prefix to send over land based analog phone system ?

I doubt they would wish at this time to replace their existing phone system 
with an all ip based system ( the cost of the ip phones would seem 
prohibitive )

Assuming the above sounds reasonable, is there any way to include a fallback 
system that would not disable the existing phone system in the event of the 
asterisk box crashing/locking etc. as dead phones is not an option ??

Many thanks for any help advice, as stated in the beginning asterisk and 
tele-comms is new to me although im experienced with linux sys-admin, 
networking etc.

Many thanks
Martin

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Re: [Asterisk-Users] Integrating with existing analog PBX

2005-09-11 Thread John Daragon

Martin Allen wrote:

Asking about inserting Asterisk between a 4 line analogue PBX and the 
outside world...


The proposed solution (with 4 x FXO and 4 x FXS using 2 TDM400 cards) 
will work fine until the asterisk box dies or suffers power failure.


An alternative may be to use 4 Sipura SPA-3000 ATAs (which have an FXO 
and an FXS port as well as an RJ45 network port (think of them as two 
ATAs an a single box...) and are cheap (see http://www.voiptalk.org )



  PSTN

***||
* *  SIP to FXO  +---+
* Asterisk* -|   |
* *  |SPA-3000   |
* * -|   |
* *  SIP to FXS  +---+
***||

  PABX


In the event of power failure the FXO port is switched directly to the 
FXS port, effectively bypassing the IP side of things completely.


Actually, I think you *could* build what you're describing just with the 
SPA-3000s, but you would, of course, lose a lot of flexibility...



jd

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