|WikiProject Computing / Hardware||(Rated Start-class, Mid-importance)|
Searching for cites for this with Google is rather odd. Doesn't show up in any books or on Scholar, but there are definitely companies that sell (or did sell) high-9 terminators.
This one in particular... is "DataMate" a brand or company? Don't know, this PDF is just a few pages from the middle of a catalog, but looking at the schematics on page 49 it's quite detailed.
Same PDF, different source: http://www.datasheets.org.uk/indexdl/Datasheet-026/DSA00466141.pdf