Simultaneous inbound/outbound calls with Asterisk

I have Asterisk running on my local server. I have only 1 telephone line and my internet connection is 2Mbps/up and 10Mbps/down and wanted to know what is the maximum simultaneous inbound and outbound calls to different extensions.

For instance if extension 10 is busy with an outgoing call, and ext 20 want to place an outgoing call can this be possible? or also can they receive calls when another extension is being used with an external caller?



as you menton about the internet bandwidth, let’s assume you are referring to the concurrent calls when using sip trunk for incoming/outgoing calls.

the maximum number of simultaneous calls depend on a number of factors like codec, bandwidth stability, asterisk configuration (eg the call-limit sip.conf) , etc.

the calculated bandwidth per channel is around 24kbps for g729 and 80 kbps for g711.

the below url could perform the calculation.


Thanks. So what I understand is that it will depend on bandwidth per call and the compression codec setup.

However, I’m still wondering if by having only 1 telephone line from my ISP/telephone provider, I still can make calls to external phone numbers as well as receive external calls to any of my extensions even when somebody else in one of my extensions is using it with an external caller?

In a regular home phone, when somebody else is calling inbound/outbound external callers will usually get a busy signal, or internal callers wont be able to place a call.



how you would receive/place to pstn? if it is via the telephone line (should be connected to a fxo card on your asterisk), then you are limited to one concurrent call just like normal home phone.

the internet bandwidth determines concurrent call limit only when you are using sip trunk to place/receive pstn call.


1 analogue line can only handle one call at a time.

“line” for a SIP trunk really has to be a marketing concept, and you need to ask your provider. There is no fundamental reason why an outgoing call even needs to go through the provider, although, at the present time, this is likely to be the beset option.