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What does each trunk (simultaneous call path) give me?

Each purchased High Volume Voice Trunk will provide you the ability to make one simultaneous call into or out of your system. If you require multiple simultaneous calls, then you will need multiple trunks. You do not need a trunk for every DID. The exceptions to this are as follows:

  1. Since Toll Free inbound calls are charged on a per-minute basis, they do not count as a concurrent call for your trunks. For example, if you have two trunks with us and have five inbound calls on your Toll Free number at the same time, you are still not using any of your High Volume Voice trunks, so you can still make or receive two normal calls.
  2. If you have bursting enabled, you can optionally choose to pay a per-minute charge to burst beyond your call paths for both inbound and outbound calling. This lets you make and receive more simultaneous calls than your purchased trunks will support.

What does High Volume mean for calling limits?

The High Volume Voice trunks assume typical small and mid-sized business (SMB) usage. The details can be seen in the Terms and Conditions and include a softcap of 3000 minutes per trunk.

Each trunk allows either one inbound or outbound call at any point in time, just like a traditional phone line or PRI channel. Additional simultaneous inbound or outbound calls are not delivered if all your channels are being used. You can purchase additional trunks to increase capacity (concurrency).

Our optional Softcap Bursting feature allows you to go beyond your softcap and pay a per-minute fee for additional calls. If you want to ensure that all your calls are always delivered in the event of a burst of traffic exceeding your concurrency, you can enable Concurrency Bursting. The extra calls will be charged at a different per-minute rates depending on whether they are Inbound, Outbound, or Canada Outbound. Enabling Concurrency Bursting in your SIPStation account will automatically enable the Top Up feature, which charges your card a set amount in order to pre-pay for metered services. See our "How Metered Services Work" wiki for more information.

Can I just purchase some inbound DIDs (phone numbers) and not purchase outbound service? I don't need the trunks.

You must purchase at least one SIPStation trunk in order to purchase DIDs. We currently do not have a plan that provides inbound-only service without a trunk.

What are my failover options?

Our Failover Service allows you to provide us with alternative delivery phone numbers and/or Backup PBXs in the event that we can't deliver a call to you.

If you do not have failover service set up, we try to send your calls to you from If you are not registered, or the attempt otherwise fails to reach your PBX, we then try sending the call to your from If that doesn't work, we give up.

Failover can prevent this from happening. If you set up an alternative phone number and/or backup PBX as a failover option, this will give us another way to deliver your call.

Do I need to have one trunk (simultaneous call path) for every DID?

 No. You can have as many DIDs as you require for your service, and you can decide how many trunks you need. The total number of simultaneous calls that can be made or received will be controlled by the number of trunks. You can add or remove trunks, as well as enable Concurrency Bursting, any time within the SIPStation Store.

I have purchased more than two trunks. Why does the SIPSTATION module in FreePBX only configure two trunks?

Whether you purchase one trunk or several trunks, your FreePBX SIPSTATION module will always configure just two connections to our primary and secondary gateways. Don't worry – this is normal. The number of trunks is referenced in the module's Account Settings section next to Channels. For example, if you have 20 trunks, then you should see 20 channels here.

 From the SIPSTATION Module in FreePBX 13: