asterisk users - Nov 2004 - Sip Phone UIP200 Accepts calls but dialing out fails

Please forgive this newbie question - I'm new both to Asterisk and to
telephony.

I have a single digium fxo/fxs card with an analog phone connected to it. I
have a single Uniden uip200 phone as well. I can dial the sip phone from the
analog phone and it works fine. When I dial the analog phone from the sip
phone, the analog phone rings but when I pick it up the sip phone does not
seem to recognize it's been picked up - it just keeps ringing. I'm
guessing
there's some sort of signaling that's not happening here, but I have no
idea
what it might be.

Any help would be appreciated.

My sip.conf:
[general]

port = 5060
bindaddr = 0.0.0.0
allow=all
context = bogon-calls

[2000]
type=friend
username=2000
secret=password
host=dynamic
defaultip=10.4.23.170
mailbox=2000
context=sip
;;;;;;;;;;;;;;;;;;;;;;

My extensions.conf:
[general]
static=yes
writeprotect=yes

[globals]
LOCALCALLS=_NXXXXXX
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
[longdistance]
exten => _1NXXXXXXXXX,1,Dial(Zap/4/${EXTEN}|20,t)
include => local
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
[local]
exten => ${LOCALCALLS},1,Dial(Zap/4/${EXTEN}|20,t)
exten => ${LOCALCALLS},2,Gotoif($[${DIALSTATUS}
CHANUNAVAIL]?channelunavailable,1,1)
include => internal
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
[internal]
include => analog
include => sip
include => special
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
[special]
exten => 1999,1,VoicemailMain(${CALLERIDNUM})

exten => 11,1,Playback(tt-monkeys)
exten => 11,2,Hangup

exten => 12,1,Milliwatt()
exten => 12,2,Hangup

exten => 13,1,SayUnixTime()
exten => 13,2,Hangup
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
[analog]
include => timeout
include => longdistance
include => 1000extensions
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
[sip]
include => internal
include => 2000extensions
include => timeout

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
[1000extensions]
exten => 1000,1,Dial,Zap/1|5
exten => 1000,2,Voicemail,u1000
exten => 1000,3,Hangup
exten => 1000,102,Voicemail,b1000
exten => 1000,103,Hangup
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
[2000extensions]
exten => 2000,1,Dial(SIP/2000,20)
exten => 2000,2,Voicemail(u2000)
exten => 2000,3,Hangup
exten => 2000,102,Voicemail(b2000)
exten => 2000,103,Hangup
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
[pstn]
exten => s,1,Wait(1)
;exten => s,2,Goto(analog,1000,1)
exten => s,2,Answer
exten => s,3,DigitTimeout,3
exten => s,4,ResponseTimeout,10
exten => s,5,Background(demo-abouttotry)

exten => t,1,Playback(vm-goodbye)
exten => t,2,Hangup


exten => i,1,Hangup

include => 2000extensions
include => 1000extensions
include => special
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
[bogon-calls]
exten => _.,1,Congestion

[timeout]
exten => t,1,Playback(tt-somethingwrong)
exten => t,2,Hangup
exten => t,102,Hangup

[channelunavailable]
exten => i,1,Playback(tt-weasels)
exten => i,2,Hangup