PBX 607 and 608 cord switchboards

Because some participants have telephone experience, I am posting this here.

I wonder if anyone is familiar with the Bell System's model 607 and 608 cord PBX (private branch exchanges) switchboards and particularly their automated features in service.

The 607 looks like a typical switchboard--black with keys and cords--but has automated features: (1) ringing starts and continues automatically when the cord is plugged in with a signal, (2) flashing is automatically done and remains on until answered. On other models, the operator must manually continue ringing (pressing the ringing key in the appropriate cadence and advising the caller), and must watch for flash recall signals.

The 608 had similar features but was modern in appearance (it was Bell's last cord board). It was white with narrow cords and all push button instead of levers.

Both could be used in dial or manual PBX service. (Manual where the PBX made all connections, dial was where extensions could dial each other or an outside line without the operator.) Both were used in Centrex (direct inward calling) but Centrex usually used consoles.

I was wondering how their automated features improved service.

It seemed many motels used 608s.

The real change in PBX switchboards was going to cordless consoles, where no disconnect was necessary and all features were automated. The wide availability of Centrex helped too. My impression is that cord switchboards were rapidly removed from service after 1980.

public replies, please