[Asterisk-Users] Basic telephony hardware questions

[Sudhakar Chandra]

Hi,

I am in the process of setting up an Asterisk-based PBX at work. I get
the concept of how Asterisk works pretty decently. I am more confused
about the proliferation of TLAs like FXO, FXS, TDP, SIP, ....

After some intense reading I have come to some understanding of the
hardware I need to set things up. I am doing this in India and am
getting a friend of mine bring the cards with him when he comes here in
a couple of weeks. I don't know when my next trip to a place of abundant
Asterisk-capable hardware will be. So I cannot afford making the wrong
decisions. I need to live with my choice for atleast the next 4-6 months.

My Setup
--------
Our office currently has 3 (to expand into 4 in the next few months)
incoming PSTN lines. All these lines have RJ11 terminations. There are a
couple of hundred employees working in the office. But not all of them
need or have a phone on their desktops.

My Requirements
---------------
I need about 10-12 POTS phones to be connected to the PBX. When their
extension is dialled, they need to ring. I need about 3 IP-phones to
connect to the PBX over Ethernet. There will be some 50 users who will
use soft phones on their desktops to connect to the PBX to make and
receive calls. I also need IVRS for incoming calls and voicemail for all
the extensions.

Based on all of the above:

* The cheapest option for me to get started seems to be 4 Digium PCI
cards on a box running Asterisk. Will a setup with an Asterisk box with
4 Digium cards work?

* I have identified 'TDM04B - 4-port FXO bundle' as the card I need to
connect to the incoming PSTN lines. Is this identification correct?
Also, will the incoming RJ11 terminations connect to this card? Or do I
need something else?

* I have identified 'TDM40B - 4-port FXS bundle' as the card I need to
connect my in-office POTS phones. Is this identification correct? Also,
will these cards enable the connection of RJ11 cables connecting to the
POTS phones?

* What do I need to connect to my local 100-base-T LAN to the PBX? I
want desktops on the LAN to be be able to run soft phones and connect to
the PBX. Do I need any other card?

* Similarly, do I need anything extra on the Asterisk box to connect the
IP phones?

* What are TE410 and TE405 cards used for?

Any help will be appreciated.

Thaths
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