An EL device sends telephone data Packets over a LAN using UDP protocol. Most EL generated UDP packets are 83 characters long. Whozz Calling? “Full-featured” devices are also capable of sending detail records, which are only 52 characters long. There are other packets sent of varying lengths, but are only transmitted when devices boot-up or are invoked by a command sent to the unit. All packets start with an identifier “^^” followed by the unit number and the serial number. A “$” identifies the remainder of the data is a standard CallerID.com data stream. It is sent as ASCII text.
Below is an example of the data contained is a packet:
^^<U>nnnnnn<S>nnnnnn$01 I E 0000 G A2 12/17 04:54 PM 770-263-7111 CALLERID.COM___
The ^^<U> are ASCII characters, followed by six binary numbers (nnnnnn), followed by <S> , followed by six more binary numbers, an ASCII $ , and finally the ASCII data stream. Note that the 15 character name field is padded with spaces (in this example, 3 spaces).
If you were to look at the actual pack with a network snooper program such as Wireshark, the entire IP packet would look like the following.
The Ethernet header is in red, the IP header is in black, and the UDP header is in green and the UDP data is in blue. As you can see, the binary unit number is 00-00-00-00-89-79 (decimal 35,193) and the serial number is 00-00-00-84-48-84 (decimal 8,669,316).