Question:  I have ICS-52 and ICS-92 panels that I want to use on a MTX+2 matrix.  I opened up to look at the EPROM version, it says 710414E, ICS-92/52, IC8, (MX+3).  My main frame is a MCF-10 Matrix +2 and is not recognizing the stations.  Is there any way I can downgrade the EPROM to Matrix +2?
Answer:  The EPROM used in the Matrix +3 version ICS-52/92 station (29C256) is different than the EPROM that was used in the Matrix +2 version (27C256) for this panel. Clear-Com no longer carries parts for the obsolete Matrix +2 product line nor do they service this product line any longer (Matrix +2 was obsolete in 1997), but the EPROM is still available via 3rd party web sources.  The obsolete part # for this EPROM was 480156, the data sheet for this EPROM is attached below.  For ICS-52/92 panels the PDIP28 style package was used.
The other part of the ICS-52/92 panel that is version dependant is the comm card, in order for it be M+2 compliant the version has to be COM-1A (part # 710464), this is the small card that is seated above the main ICS-52/92 pcb. Older version comm cards (part# 710291 rev A or D) are also compatible with Matrix +2 panels.