Although this is an old post - I found a model 15A. Zetron very nicely gave me a 15B and 15P manual which does not match close. Zetron claims that is the oldest in their archive. I just need this to wire in to our backup for the backup unit. Any chance someone has a 15A manual to share?

Obtained a Zetron model 10 A hooked to an old Radius. Would like to change the ab tone group from (12) to (22). A manual would be real nice if someone had an electronic copy. Thanks