This is Icom's version of the NXDN protocol. The abbreviation is Icom Digital Advanced System.
Please see the Icom IDAS System Features website for a complete description of the system features of IDAS.
Also see the Understanding IDAS trunking Thread in the forums area.
Can it be Decoded?
Apart from using an actual Icom radio, the following methods are possible;
Data for Scanners