From the bottom up …
SndIns – Direct command to turn device 05:16:88 On at Full Bright
Parms3-5 to Insteon device address 05:16:88
Parm 6 – Flag byte – 0x – first 4 bits indicate Direct message
Parm 7 – cmd1 value – 11 – On command
Parm 8 – cmd2 value – FF – Full Bright
InsStdMsg – ACK response from Direct On command
Parms3-5 from Insteon device address 05:16:88
Parms6-8 to Insteon device address 06:4C:94
Parm 9 – Flag byte – 2x – first 4 bits indicate ACK of Direct message
Parm 10 – cmd1 value – 11 – On command
Parm 11 – cmd2 value – FF – Bright level
Next SndIns is querying the device status and the last InsStdMsg is the ACK response to the query.
You should note that NOT ALL KeypadLinc devices respond to Direct commands the way this one is. It is also necessary to create a Scene with EZSrve as the Controller and the KPL as the responder to turn On/Off other than button 1 even on this KPL.
On the SmartLabs web site (insteon.net ?) they have a public document Insteon Details which describes what some of the Insteon messages look like. They do not make public what all the commands look like. You can purchase a developer subscription to gain access to what they consider confidential information.