From Privateline.com is this description of MECOBS by Ronald Briggs.
[Editor Tom Farley's note. Included in the Privateline.com page are discussions of personal remembrances and the article 'Mechanized Combined Line and Recording System", which appeared in the January, 1973 GTE Automatic Journal. The authors were A.B. Behnke, J.A. Calder, and W.R. Trudo. Click here for a partial, uncorrected scan of this document (internal link.]
In reading through the MCLR documentation, the system seems like a TSPS type concept answered and operated at a cordboard position. It mentions the switchboard could only be used in either "MCLR" (using SATT equipment) or (manual) cord mode, but not both at the same time. The "Dial Rear/Flash Key" description on page 264 details how the flash function is used to identify the trunk in the multiple that the caller is on if the call needs to be manually handled, thus removing the SATT ticketer from the call and the operator. It sounds similar to another system idea you forwarded to me last year, I believe from Northern Electric, that was quite a bit more advanced but not as advanced as MECOBS.
MECOBS, though, was different. All operations and keying were accomplished using the unit installed in each position, only two keys illuminated (ST, NUM EXPR (same as Error)) and the display only displayed two digit error codes. I came close to purchasing a three panel 3CL position with MECOBS, had all the keys been in the unit I would have (it was missing the CA TMG key). Attached are pics of it, the keyshelf unit keys have been rearranged from their original positions in the unit. The display unit is the upper left corner, the keyset was lower right, the black KP keys were lower left, the blue function keys were between the black keys and display, the green class charge keys were above the keyset to the right of the display. ST was to the right of "0", below "9", NUM EXPR was above "3".
MECOBS completely eliminated the need for mark sense tickets, everything was keyed - toll, credit, trouble, coin deposits. The only time tickets and the round KP keys to the right of the MECOBS unit were used was when MECOBS was down (NUM EXPR flashing 30 IPM, display reading "99").
From the lead article:
Mechanized Combined Line and Recording System by A. B. Behnke, J. A. Calder and W. R. Trudo GTE Automatic Electric Laboratories (partial, uncorrected scan, internal link)
"Historically, CLR (Combined Line and Recording) cord toll switchboard operation resulted in the operator manually preparing a ticket on subscriber originated calls. This method of operation included the marking of called and calling number, recording the start and completion of conversation, and the monitoring of supervisory lamps for disconnects. This article describes a new development which offers an economic method of 'machine ticketing' CLR calls that results in minimum operation effort in completing these calls. This system can function with existing SATT (Strowger Automatic Toll Ticketing) systems, and is primarily designed for use in small to medium toll centers having a maximum of 125 cord toll switchboard positions."