https://arttel.ru/
DBL Technology Co., Ltd.
www.dbltek.com
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:
c) Mode 3
SIP Message format:
The "To" field in the SIP INVITE message contains the phone numbers of both the called and calling
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:
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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: W
Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, NOTIFY, REFER, REGISTER, MESSAGE, INFO, SUBSCRIBE
Content-Type: application/sdp
Content-Length: 226
parties. These two numbers are concatenated by using the asterisk (*) character with the number
of the called party in the front.
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
Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, NOTIFY, REFER, REGISTER, MESSAGE, INFO, SUBSCRIBE
Content-Type: application/sdp
Content-Length: 226
GoIP User Manual
Technical Support: support@dbltek.com
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