This is what i had to do to setup my $7.95 Miami inbound DID with
www.Inphonex.com
1) sign up on their site for pay as you go outbound service $9.95 + $1.00 tax
2) After signing up you will have a virtual number assigned to you by INPHONEX
3) Email
sales@inphonex.com that you want to purchase an incoming DID (since you can't do it on the website directly as of yet)
4) They send you an email giving you instructions on where/how to sign up for incoming DID number
5) after choosing and purchasing a DID, log in to inphonex account on their site and click on control panel
6) now under control panel you will see everything needed to setup Asterisk
7) edit sip.conf for Asterisk with these lines
;#####sip.conf###################################
[general]
port = 5060 ; Port to bind to
bindaddr = 0.0.0.0
insecure=very ; I had to add this or i would get chan_sip.c:9046 (handle_request_invite: Failed to authenticate user) errors on the caller iD and it would get redirected to inphonex's voicemail.
disallow=all ; Disallow all codecs
allow=ilbc ;inphonex supports only ilbc and G729 I didn't feel like purchasing a G729 license from digium so I use ilbc, sounds fine
register => virtualacctnum
ass:virtualacctnum@sip.inphonex.co m:5060/ext
;use the virtual account number not your actual DID in the above register => line
;'ext' at the end of this line can be any extension you choose that will correlate with an extension in extensions.conf
[inphonex]
type=peer
username=virtualacctnumber
fromuser=virtualacctnumber
secret=pass ; password used to login their website (same in register =>)
host=sip.inphonex.com
nat=yes ; my asterisk is behind nat
canreinvite=yes
context=inbound-inphonex ; context to be used in extensions.conf for inbound
8 ) edit extensions.conf
;#########extension.conf########################## ###
[globals]
OFFICE=SIP/x101 ; my sip phone in the office
;remember replace 'ext' with the number you used at the end of the register => line in sip.conf
[inbound-inphonex]
exten => ext,1,Wait(1) ;Wait a second, and to get the CallerID information.
exten => ext,2,Playback(support) ; play initial greeting/recording
exten => ext,3,Dial(${OFFICE},20,tr) ; dial my sip phone for 20 sec
exten => ext,4,SetCallerID(${IDCALLER}) ; im not there? set call id to pass to my cell phone
exten => ext,5,Dial(IAX2/login@voipjet/cellphone#,10,tr) ; dial my cell phone , and seamlessly fw call to it. I use voipjet
exten => ext,6,Playback(busy-on-call) ; switch to a on-call message if i didnt pick up both cell and sip phone
exten => ext,7,Voicemail(1) ;leave voice mail
exten => ext,8,Hangup() ; hangup the call
9) done
This is what I did to get my office up with Inphonex.com, I chose Inphonex because they are a local Miami,fl company and their servers are also local (15ms ping). I'am by no means an Asterisk expert (yet), So this may have mistakes, but I'am just sharing what I did to get it to work for me.
Cheers,
Josh
How to setup Asterisk with Inphonex.com 
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