DBL Technology GoIP User Manual page 57

the Call OUT via GSM parameter of the device must be enabled and the Forward Number associated
with this parameter is set to the phone number of the SMS sender.
To achieve the Call Back function, the SIP server calls the called party via its phone network and then
calls the SIP number. Since a call to this SIP number is set to forward to the phone number of the SMS
sender, both the called and calling parties can then be connected.
Example:
SMS content = 8675588228822
Sender's number = 861380000000
SIP Server IP = 192.168.2.1
SIP Number = 20001
The INVITE message sent to the SIP Server is:
INVITE sip:8675588228822@192.168.2.1:5060;transport=udp SIP/2.0
Via: SIP/2.0/UDP 192.168.2.237:5060;branch=z9hG4bK363969813
From: <sip:20001@192.168.2.1:5060>;user=phone;tag=65248630
To: <sip:8675588228822@192.168.2.1>
Call-ID: 117025903@192.168.2.237
CSeq: 2 INVITE
Contact: <sip:20001@192.168.2.237:5060>
Max-Forwards: 30
User-Agent: DBL
Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, NOTIFY, REFER, REGISTER, MESSAGE, INFO, SUBSCRIBE
Content-Type: application/sdp
Content-Length: 226
c) Mode 3
SIP Message format:
- The "To" field in the SIP INVITE message contains the phone numbers of both the called and calling
parties.
number of the called party in the front.
- The "From" field contains the SIP number of the line that is associated with the GSM channel
Example:
SMS content = 8675588228822
Sender's number = 861380000000
SIP Server IP = 192.168.2.1
SIP Number = 20001
The INVITE message sent to the SIP Server is:
http://www.dbltek.com
These two numbers are concatenated by using the asterisk (*) character with the
Sending Message to 192.168.2.1:5060:
INVITE sip:8675588228822*8613800000000@192.168.2.1:5060;transport=udp SIP/2.0
Via: SIP/2.0/UDP 192.168.2.237:5060;branch=z9hG4bK363969813
From: <sip:20001@192.168.2.1:5060>;user=phone;tag=65248630
To: <sip:8675588228822*8613902994477@192.168.2.1>
Call-ID: 117025903@192.168.2.237
CSeq: 2 INVITE
Contact: <sip:20001@192.168.2.237:5060>
Max-Forwards: 30
User-Agent:DBL
GoIP User Manual
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