-- Executing SetCallerID("SIP/home-081b7fd8", "1234") in new stack
    -- Executing Dial("SIP/home-081b7fd8", "IAX2/gradwell/1234") in new stack
Jun 19 21:14:03 WARNING[27397]: chan_iax2.c:8058 iax2_request: Unable to create translator path for unknown to gsm on IAX2/gradwell-2
    -- Hungup 'IAX2/gradwell-2'
Jun 19 21:14:03 NOTICE[27397]: app_dial.c:1079 dial_exec_full: Unable to create channel of type 'IAX2' (cause 0 - Unknown)
  == Everyone is busy/congested at this time (1:0/0/1)



  * Name       : gradwell
  Secret       : <Set>
  Context      :
  Mailbox      :
  Dynamic      : No
  Callerid     : "" <>
  Expire       : -1
  ACL          : No
  Addr->IP     : 193.111.201.75 Port 4569
  Defaddr->IP  : 0.0.0.0 Port 0
  Username     : <removed>
  Codecs       : 0xf900 (g729)
  Codec Order  : (g729)
  Status       : Unmonitored
 Qualify        : every 60000ms when OK, every 10000ms when UNREACHABLE (sample smoothing Off)


iax.conf

[general]
bandwidth=low
disallow=all
allow=g729
jitterbuffer=no
forcejitterbuffer=no
tos=lowdelay
autokill=yes

[gradwell]
type=peer
username=<removed>
secret=<removed>
host=iax-out.gradwell.net
disallow=all
allow=g729



extensions.conf bit

[gradwell]

exten => _0.,1,SetCallerID(<removed>)
exten => _0.,2,Dial(IAX2/gradwell/${EXTEN})

[home]
type=friend
context=internal
secret=<rempved>
callerid=Home <5004>
accountcode=home
host=dynamic
defaultip=192.168.1.106
nat=no
canreinvite=yes
dtmfmode=rfc2833
mailbox=5002 
disallow=all
allow=gsm        
allow=g729
vmexten=8501
qualify=yes
notifyringing=yes
subscribecontext=public