Incoming routes configuration

Hi, I’m Roberto and I have some problems with the configuration of inbound routes. First, I desire to inform you what are the steps done which are ok:

  1. Asterisk installation: ok
  2. estensions configuration: ok
  3. calling between estensions: ok
  4. creating queues, conference and ring groups: ok
  5. to obtain a clling toward an externalnumber, it’s necessary to create a trunk.Now, I want to call numbers which are internal in an other PBX. In other words, Asterisk has to communicate with an other PBX, which is not Asterisk.
    I create a Trunk SIP and in the OUTGOING SETTINGS section, the parameters I have configured are the following:
    host=IP address of the PBX I want to reach
    After that I go into the OUTBOUND ROUTES section and I set what are the rules for the outgoing calls. WITH THESE SETTINGS, EVERYTHING WORKS!!!
    After that, I want to set the incoming routes: different roads I followed but the result was the same: NO INCOMING CALLS!!!
    Can you help me please, specifying what can be mistakes I commit??
    I wait for your response please.
    Thanks so much for your help and please, sorry for my poor English.

At a minimum, you need

host=*IP address of the PBX I want to reach*

Reload. After which you can monitor the call progress with

$ asterisk -r
cli> core set verbose 3
cli> <watch the call flows here>