We have 4 people call us from around the country at once and it causes our phones to be busy.

We want to be able to have at least 8 people call us at once without anyone getting the busy signal. There will almost always be people calling each other internally, up to 10 at a time.

We have 4 analog lines coming into a Dell server that has a Digium AEX410PELF PCIe card in it.

Do I have to buy another one of these cards (or an 8 port version) or can I just configure Asterisk to handle more simultaneous calls somehow?

Is it as easy as adding the second card in and getting a few settings changed?

We will have the phone company install an additional 4 analog lines coming in for us if needed.


You're limited by the number of analog lines you have connected. Each line can handle only one call at a time - so no matter what settings you change, your system won't have any higher external capacity. Note that if any call has an endpoint outside your organization - whether an inbound or outbound call - it needs a free line.

You need a bunch of pieces - if you want to be able to have 4 more simultaneous calls, you need to get your telephone company to install 4 more lines, with the associated cost and time. Then you'll have to install another analog line card to accept the new lines. Finally, you'll need to configure Asterisk to accept calls from the new card and send calls out it.

  • 2
    I'd change the order around: first get the new card and install it, configure it in asterisk, test it and then add it for incoming calls, and when that is all ok, request more lines in the same group from your phone company. Otherwise there will be a period of time where the phone company routes the extra calls to your system but you can't process them yet. A busy signal is a better indication than ringing without answer in this case. – Koos van den Hout May 9 '12 at 13:15

If by "calling" you mean from the PSTN, then you will have to add another card. It should be pretty much as easy as adding the card and using the manual to tell you how to get Asterisk to use it.


Of course, you will not only need the second card but 4 more working POTS telephone lines.

If you might want more lines than four times the number of suitable slots in the server, consider renting ISDN lines instead if available, there are cards available which are quad BRI so eight voice channels to a card (and even quad PRI cards which do a ludicrous amount of channels with the appropriate line. But a PRI line will probably exceed your budget...)

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