[fs]
type=friend
host=dynamic
port=5060
context=phones
dtmfmode=rfc2833
insecure=port,invite
qualify=yes
disallow=all
allow=ulaw
allow=alaw
qualify=yes
secret=1234

[extensions]
exten => 1001,1,Dial(sip/fs/1001)

/etc/freeswitch/sip_profiles/fs.xml
<include>
    <gateway name="fs">
      <param name="username" value="fs"/>
      <param name="password" value="1234"/>
      <param name="realm" value="192.168.1.5"/>
      <param name="from-user" value="fs"/>
      <param name="from-domain" value="192.168.1.5"/>
      <param name="proxy" value="192.168.1.5:5060"/>
      <param name="expire-seconds" value="800"/>
      <param name="register" value="true"/>
      <param name="retry-seconds" value="60"/>
      <param name="context" value="public"/>
      <param name="caller-id-in-from" value="false"/>
    </gateway>
</include>

/etc/freeswitch/dialplan/10.xml
<include>
  <extension name="call_in">
    <condition field="destination_number" expression="^(402)$">
        <!-- Звоним -->
         <action application="bridge" data="user/1001@sip.internal"/>
        <!-- Кладем трубку -->
        <action application="hangup"/>
    </condition>
  </extension>
</include>