[asterisk-users] Best way to get 60+ analogue extensions.

[Rob Hillis]

Duncan Turnbull wrote:
> Hi All
>
> I am looking at a replacement for a hotel PBX which requires at least 60 
> analogue extensions.
>
> I tend to use Sangoma equipment but haven't tried this many analogue 
> extensions before. I am interested in anyone's experience of which 
> server platform literally fits and copes well with multiple cards, and 
> the choice of Digium vs Sangoma or something else.
>   

You have several options here, however due to the power requirements, I
wouldn't recommend you use either the Sangoma or Digium analogue cards
here - providing ring voltage to that many extensions is likely to
over-tax the power supply in the server.

I'd either be looking at three channel banks (3 24 channel channel banks
would give you a total of 72 analogue channels) or two Xorcom Astribanks
which would likewise give you up to 64 channels.

The Astribanks are probably a cheaper way to go since they connect to
your server via USB rather than T1/E1 ports.  However, I haven't had any
experience with multiple Astribanks connected to the same server, so
there may be issues there that I'm not aware of.  Channel banks are
certainly the proven and reliable technology, but will be significantly
more expensive since they connect to your Asterisk server via T1/E1 links.

> I may need an ISDN PRA inbound but am working hard to have the inbound 
> lines via SIP, but if I do that means at least 4 slots on this plan.
>   

You'd need to be very sure of the bandwidth and quality of connection to
your VoIP provider to go with SIP for more than half a dozen channels. 
This kind of connection can easily be far more expensive than a
traditional T1/E1 line, so I wouldn't be pushing so hard for SIP.

If you were to use channel banks, you would most likely end up with a
four port T1/E1 card and would only be using three of those channels,
leaving a spare one for an incoming T1/E1 line.

If you were to use Astribanks, you would have plenty of space in the
server to include a T1/E1 card.