extensions.conf
-----------------
clearglobalvars=no
[globals]
CONSOLE=Console/dsp                         
IAXINFO=guest                               
TRUNK=Zap/g2     

[default1]
exten => s,1,Wait,1
exten => s,2,Answer
exten => s,3,Dial(SIP/101,20)

; Extension 101 for dallas
exten => 101,1,Dial(SIP/101,20)
exten => 101,2,VoiceMail(101@default)
exten => 101,3,PlayBack(vm-goodbye)
exten => 101,4,HangUp()

[default2]
exten => s,1,Wait,1
exten => s,2,Answer
exten => s,3,Dial(SIP/102,20)

; Extension 102 for nate
exten => 102,1,Dial(SIP/102,20)
exten => 102,2,VoiceMail(102@default)
exten => 102,3,PlayBack(vm-goodbye)
exten => 102,4,HangUp()

zapata.conf
--------------------


[channels]
language=en
usecallerid=yes
hidecallerid=no
immediate=no

signalling=fxs_ks
echocancel=yes
group=1
channel=1
context=default2

signalling=fxs_ks
echocancel=yes
group=2
channel=2
context=default1


the error
--------------


    -- Starting simple switch on 'Zap/1-1'
[Jun  7 07:30:28] NOTICE[8430]: chan_zap.c:6351 ss_thread: Got event 18 (Ring Begin)...
[Jun  7 07:30:29] NOTICE[8430]: chan_zap.c:6351 ss_thread: Got event 2 (Ring/Answered)...
[Jun  7 07:30:33] NOTICE[8430]: chan_zap.c:6351 ss_thread: Got event 18 (Ring Begin)...
  == Starting Zap/1-1 at default,s,1 failed so falling back to exten 's'
  == Starting Zap/1-1 at default,s,1 still failed so falling back to context 'default'
[Jun  7 07:30:33] WARNING[8430]: pbx.c:2450 __ast_pbx_run: Channel 'Zap/1-1' sent into invalid extension 's' in context 'default', but no invalid handler
    -- Hungup 'Zap/1-1'
    -- Starting simple switch on 'Zap/2-1'
[Jun  7 07:30:43] NOTICE[8432]: chan_zap.c:6351 ss_thread: Got event 18 (Ring Begin)...
[Jun  7 07:30:44] NOTICE[8432]: chan_zap.c:6351 ss_thread: Got event 2 (Ring/Answered)...
[Jun  7 07:30:48] NOTICE[8432]: chan_zap.c:6351 ss_thread: Got event 18 (Ring Begin)...
    -- Executing [s@default2:1] Wait("Zap/2-1", "1") in new stack
    -- Executing [s@default2:2] Answer("Zap/2-1", "") in new stack
    -- Executing [s@default2:3] Dial("Zap/2-1", "SIP/102|20") in new stack
[Jun  7 07:30:49] WARNING[8432]: chan_sip.c:2738 create_addr: No such host: 102
[Jun  7 07:30:49] WARNING[8432]: app_dial.c:1099 dial_exec_full: Unable to create channel of type 'SIP' (cause 3 - No route to destination)
  == Everyone is busy/congested at this time (1:0/0/1)
  == Auto fallthrough, channel 'Zap/2-1' status is 'CHANUNAVAIL'
    -- Hungup 'Zap/2-1'