Number 61388A is a Merlin II ring generator but I have no list of a 61389A either. Maybe it's something made by another company. It doesn't seem to be in the Merlin II manufacturing era.
Here's a point, though,---can't you upgrade to a Legend CPU module---and then you basically have a Legend?? That would certainly take it out of the realm of "ancient technolgy" in my book. Let's wait for the Avaya moderators to join in. They're the experts. Good Luck.

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