Inbound Routes (Incoming Calls)This is where the behaviour of incoming calls from all trunks is being handled.
When an incoming call from PSTN or VoIP trunk is received, asterisk needs to know where to direct it. It can be directed to a ring group, an extension, Digital Receptionist or Queue. For this purpose, Inbound Route needs to be set up.
Select the Inbound Routes selection in the left bar of the screen.
Initially, I have set all my incoming calls to be directed to Ring Group 10 as illustrated below (later on in this guide I will create a digital receptionist for this purpose).

only put in the following data. The rest are optional.
· DID Number: 8882593347 (This is my Pennytel SIP number)
· Fax Extension: Disabled (I do not require fax facility here)
· Privacy Manager: No
· In the radio button, I enabled Ring Group 10 (AllPhones). I want all my incoming calls from Pennytel trunk to ring all the phones.
For each extra trunk, a corresponding inbound route may be created. All incoming calls from all the different trunks that you may have can have their own individual characteristic by judicious deployment of the time condition facility available in FreePBX (to be discussed later on).
At least one Inbound Route must be created for TRIXBOX to answer incoming calls. This includes calls from PSTN trunk as well.
As usual, you will need to click on the red bar on top of the screen after each time you submit a new Inbound Route.

To handle the calls that come in without Trunk ID, you may create a Catch-All route. In my case, I simply create an Inbound Route with the DID Number and Calling ID Number fields left blank. This will have the effect of handling all calls from trunks that does not have an Inbound Route created (which includes all calls from PSTN and incorrectly created incoming route). As a matter of fact, this can be the only Inbound Route that you will need if you deploy IVR (to be discussed later on). Besides, without this inbound route created, your 7777 simulated calls may not work.
More detalis
here