Solved SIP Trunk Sim Call Limit

[jcostlow]

Hi Everyone,

I am pretty sure I know the answer to this but figured I would ask to be safe in case there is some setting I don't know of.

We are looking at moving one of our law firms from their legacy PBX that has the SIP being converted to PRI once the contract is up to 3CX. When I add the carrier it usually has the simultaneous calls set to 10. For the customer would changing the simultaneous calls to 48 be all that is needed to properly set the trunk up for 48 call paths?



Most of my current installs have had 4-6 lines so I have left it set to 10 in the event we add more trunks.

 

[cobaltit]

It seems fairly obvious but yes, that setting controls the number of simultaneous calls on a trunk. Do note that is has no bearing on the license limit. So you could set it to any number but the lowest number, be it the trunk setting, the license limit, or the provider limit, will be the limiting factor on the number of calls.

 

[leejor]

With PRI, channel 24 is used for signalling on the first span, leaving 23 channels for voice. If the second span is a part of the same trunk group at the provider (or is a separate trunk group), and has also been assigned a D channel, so it can function on it's own if the first span fails, then it too will only have 23 voice channels available.

 

[jcostlow]

It seems fairly obvious but yes, that setting controls the number of simultaneous calls on a trunk. Do note that is has no bearing on the license limit. So you could set it to any number but the lowest number, be it the trunk setting, the license limit, or the provider limit, will be the limiting factor on the number of calls.

Thanks, That is what I figured. I just wanted to make sure I didn't miss anything.

With PRI, channel 24 is used for signalling on the first span, leaving 23 channels for voice. If the second span is a part of the same trunk group at the provider (or is a separate trunk group), and has also been assigned a D channel, so it can function on its; own if the first span fails, then it too will only have 23 voice channels available.

Yep I just put 48 as I am used to the previous PBX we sold showing the card with 24 ports but only using 23 channels. Current PBX has 2 PRI cards allowing us to have 46 trunks. Just wasn't thinking when I posted.