Hardware setup

Hi Guys!

I am new and I want to say hello to everybody!

I am coming with a perhaps “newbie” question. A friend asked me to build up a Asterisk system for his small European company. 2 mgr. seats, 6 employees, 2 faxes, 1 ISDN modem and some additional desk phones. So in sum ~15 extensions. The current setup is a “traditional” PBX connected with 4xBRI EuroISDN.

Question 1:
Which is the best BRI EuroISDN interface card for a Asterisk machine?

Question 2:
All 6 people are using DECT phones and there are just a few desk phones. So they want to keep their mobility, which means that they want to keep their phones. To keep these phones I will need a FXS gateway or I have to replace all phones against wireless IP Phones (which is much to expensive).
I informed me and saw that there are some possiblities:

  • FXS Interface cards
  • ATA with 2 ports, 4 ports, 8 ports?
  • ATA with 4 ports
  • Media Gateway with T1 or E1 interconnection to a ISDN interface card.

What is the best solution? Which is the cheapest one? What is the best hardware for the FXS gateway?

Question 3:
As mentioned above they are using an ISDN modem which gives a external partner service connectivity for some machines.

How do I connect this one to the Asterisk server?

Question 4:
They asked me for a GSM gateway. I saw that the boxes begin at 2 lines and can connect via ISDN BRI or FXS/FXO.

Do you have recommendations? Do I need any additional hardware except the GSM gateway itself?

I would really appreciate your help,
and thanks for your help in advance,

Can nobody give me some hints?

Please help me!