Test Set Phone
(A.K.A., the "butt-set", as in "butting into a conversation" which is one use for this item)
My Lineman's Test Set
Monitor/Talk
Switch
Test Clip
For making temporary "clip-on" connections
Genuine Bell
of course!
Rotary Dial
Belt Hanger
"The term "butt-in" and "butt-out" came from telephone terminology. The reason for the name Butt-set, is that this device is named after the inventor Mr. Buttinsky. I have seen cut sheets from Graybar for Harris -Dracon TS-21 sets that refer to them as Buttinsky's. The telephone industry was one of the largest employers, so it is not surprising that many phone-related terms became common usage." - James Stettler
This is not a phone like you would have in your home unless you are a phone collector like me! It was used by the "Telephone Repairman" to troubleshoot problems in phone line circuits or to monitor, break in (or "butt in") to a telephone conversation already in progress.
The following information was contributed by Dennis D Hock and Steph Kerman:
"The official Bell System model number of a test set like this is 1013 if equipped with permanent clip leads for an installer/repairman or 1014 if equipped with an interchangeable test cord plug for CO/PBX use. The earlier 1011 variations were distinguished by letter suffixes as was the later 1015 test set with pushbutton dial. However no difference in 1013/1014 code regardless of whether it was blue, yellow or orange. (Obviously they were already beginning to "lose it" when they did this.)" - Steph Kerman
"The circuit is a very basic type which utilizes a capacitor, resistor, inductor, T1 transmitter and a LA1 i think receiver. The Monitor switch is used to create a circuit similar to that in the 302AA, 500E/F sets, that is a high impedance bridge to monitor. It is not high enough that it won't attenuate data service however. This is formed by using the capacitor in series with the receiver the switch and the line. In talk mode the inductor in series with the transmitter and bridged by the receiver and the capacitor." - Dennis
"Actually, the iron core device is a bridging transformer with hi-Z (10K?) primary winding to permit monitoring on data circuits at a much higher impedance than would be possible without a transformer. The transformer is as best as I recall used as an inductor during talking to keep DC out of the REC so that the REC can be protected with a varistor for click suppression.... a refinement not found on the 1011 which used a simple series circuit.
There is a BSP in the 100, 103 or 106 BSP divisions describing various cord configurations. and showing a schematic.
BTW the dial is a standard #10A Trimline dial except equipped with a porcelain number plate." - Steph Kerman
