To summarise the remainder of this document, our equipment is designed
to function from 1980 to 2079, and will give no problems at the transition
from 1999 to 2000 provided that the current firmware is fitted.
Before anything else, it is worth pointing out that none of the Dialtone outstations is based on PC technology, so a large part of what is written about the Year-2K problem does not apply since the units' firmware has little in common with a PC's BIOS. Having said that, in common with the majority of PCs the DT500, 600 and 700 models do use a 146818 real-time clock chip which is now understood to have certain peculiarities:
Equipment older than the DT500:Outstations which pre-date the DT500, i.e. all variants of the DT100, DT200 and DT300 together with Dialarm units and any engineering "specials" derived from these, do not store or refer to the date in any way, therefore they are inherently Year-2K compliant. However, these products are no longer supported since in some cases component parts are unobtainable, and whilst we will do our best to keep customers running we normally recommend that any of these units which remain in service should be replaced by DT600s which are currently our entry-level model.
DT500, 600 and 700:We have tested and do not anticipate any problems with the date roll-over or leap-year determination on outstations that maintain their own real-time clock and calendar, i.e. the DT500, 600 and 700; provided that these are fitted with the current version of firmware:
Timestamp calculations in the data-logging memory do not make use of the year value, and provided that the time and date setting of the outstation has not been changed manually timestamps are guaranteed to be monotonic, i.e. there will be a single transition between 31/12/99 and 1/1/00 which represents the century rollover. This is accommodated by the protocol handler in the System 100 CAMM masterstation which assumes that any two-digit year less than 80 is in the 21st century, whilst years >= 80 are in the 20th.
We suggest that in cases where the outstation's logging facilities are used that the following precautions should be taken during the last few months of 1999 if the time or date are to be decremented:
We believe that the above points apply to all released firmware revisions, however this is subject to any modifications that the manufacturers of the real-time clock devices may have introduced during the lifetime of these models.
Operation will be as expected until around 2080, whereupon the apparent
date will revert to 19xx rather than 20xx. With all current revisions of
firmware the year 2100 will be incorrectly reported to be a leap year (i.e.
the firmware takes no special steps to correct the bug in the real-time
clock chip). In all cases the year is entered as two digits with
any surplus discarded, i.e. Saturday 1st January 2000 should be entered
as DATE=7/01/01/00 rather than as 7/01/01/2000 which would be interpreted
Instation:This comprises DT500 CPU and modem cards and is used to expand logged data from the reduced form in which it is transferred from a DT500, 600 or 700. Unlike a DT500 it does not have a real-time clock chip, and applies no time-related operations to the data it handles other than reproducing the value of the last received timestamp where required.
Last updated: 27th July 2006