i2004 not registering with asterisk

Hi,
I’ve been working with Nortel PBXs for the past ten years and I’m new to asterisk. In order to get my feet wet, I’ve installed CentOS on virtualbox and installed asterisk 10.6.1. Installation went through fine. Minor hiccups, but everything resolved.

I configured an i2004 as in the unistim.conf file below.
I also included a line in the extensions.conf under the context default
(exten=>2800,1,Dial(USTM/2800@i2004)

From anywhere on our network, I can ping the virtualbox (static IP and network setting set to bridge).
From within the virtualbox I can ping anything on our network.

No matter what I do (reload unistim and dial plan) I can’t get the phone to register with asterisk. Am I missing something?

Any suggestions.

Thanks

[i2004] ; name of the device
;device=22cf922d3104
device=000ae4750133 ; mac address of the phone
rtp_port=10000 ; RTP port used by the phone, default = 10000. RTCP = rtp_port+1
rtp_method=0 ; If you don’t have sound, you can try 1, 2 or 3, default = 0
status_method=0 ; If you don’t see status text, try 1, default = 0
titledefault=Asterisk ; default = “TimeZone (your time zone)”. 12 characters max
height=3 ; default = 3, the number of display lines the device can show
; For example on a Nortel I2001 or I2002, set this to 1
maintext0=“Asterisk_Test” ; default = “Welcome”, 24 characters max
maintext1=“Terry” ; default = the name of the device, 24 characters max
;maintext2="(main page)" ; default = the public IP of the phone, 24 characters max
dateformat=1 ; 0 = month/day, 1 (default) = day/month
timeformat=1 ; 0 = 0:00am ; 1 (default) = 0h00, 2 = 0:00
contrast=8 ; define the contrast of the LCD. From 0 to 15. Default = 8
country=us ; country (ccTLD) for dial tone frequency. See README, default = us
ringvolume=2 ; ring volume : 0,1,2,3, can be overrided by Dial(), default = 2
ringstyle=3 ; ring style : 0 to 7, can be overrided by Dial(), default = 3
callhistory=1 ; 0 = disable, 1 = enable call history, default = 1
callerid=“Terry David” <555-234-5678>
context=default ; context, default=“default”
;mailbox=1234 ; Specify the mailbox number. Used by Message Waiting Indication
linelabel=“Support” ; Softkey label for the next line=> entry, 9 char max.
extension=line ; Add an extension into the dialplan. Only valid in context specified previously.
; none=don’t add (default), ask=prompt user, line=use the line number
context specified previously.
; none=don’t add (default), ask=prompt user, line=use the line number
line => 2800 ; Only one line by device is currently supported.
; Beware ! only bookmark and softkey entries are allowed after line=>
;bookmark=Hans C.@123 ; Use a softkey to dial 123. Name : 9 char max
;bookmark=Mailbox@011@54 ; 54 shows a mailbox icon. See #define FAV_ICON_ for other values (32 to 63)
;bookmark=Test@*@USTM/violet ; Display an icon if violet is connected (dynamic), only for unistim device
;bookmark=4@Pager@54321@51 ; Display a pager icon and dial 54321 when softkey 4 is pressed