Detailed
instructions are provided in document "EPROM
Replacement H55875" which can be downloaded
from
here
"On some earlier versions of the TTDM, a RAM
upgrade, and/or a circuit board upgrade, may be required
to achieve the full set of features listed above, however
a limited edition of the TTDM-PLUS software is available
that will work with all older TTDM's without extra
hardware upgrades."
To
make it easy to quickly identify which is the correct
EPROM (software) and Dallas ROM (memory) go together
with any particular version of TTDM panels the following
table can be used as a guide