5963 computer grade dual triode production dates 3504

The Labs did indeed cook up a harebrained scheme to retrofit #5-XBAR translators for SS7, which, of course, was ludicrous and was quietly dropped. You'll also note in the Record that XBAR engineering groups at the Labs also cooked up "custom calling" features, borrowed from the #2-XBAR AUTOVON switch, to retrofit #5 machines...about as good a case of "empire building" as I can show. ALL of the big 4As were gone by the mid-80s, with a smattering of #5 and 4M tandem switches still lingering in locations where a "drop in" of a 5E wasn't easily done, or where the office was simply slated for elimination from the switched network.

Last case of this I remember was the #5-XBAR at rest Valley Jct., CA. This switch was built in the '70s to do exactly what the #5 machine was originally designed to do...be a variable density end and tandem switch in one office. The 5E has all that capability, but due to some odd problems, such as analog 4 wire short haul carrier systems feeding "local loops," it took some time to get rid of, as the outside plant had to be also digitized (SLC96, etc) in order to interface directly with the switch and prevent a major and costly kludge.

Pacific Telephone, who owned the office at the time, got a "deal" on that XBAR machine, and couldn't justify installing a new, but quickly obsolete, 1A-ESS for about 500 subscribers, nor would a 1A do toll functions or digital facility inteface. Add to that fact that it was one of only five (?) end offices owned solely by AT&T after Divesbreasture, and the legal and political impediments became astounding. Also, the DVLY 5-XBAR was a very new machine, one of the last #5s built by the Oklahoma City Works before it shut down production, and wasn't fully amortized at the time. Once the bean counters saw that it was fully amortized, it was scrapped. The #5 machine in that place replaced a 100 line SXS CDO that had existed since the mid '40s. The major indie telco in that whole desert area at the time was formerly Califoria Interstate Telephone, which was gobbled up by ConTel in the '60s. They had all manual board toll service and open wire C carrier way into the '70s, while rest Valley had XBAR DDD.

And no, the DVLY #5-XBAR machine was never retrofitted for SS7.