[GreenKeys] Illinois Bell 1966-1972.

[Don Robert House]

Chicago Northwest Suburban Teletype and Data circa 1966-1972... My six  
years included lots of learning.
After 1972 I went "inside" to the Data Test Center and then on to  
circuit design and transmission engineering.

At the beginning I was the Teletype Dispatcher for our area.  The job  
was challenging and interesting.
You had to know the talents of the crew and how to keep the men  
working without passing each other on the roads.
You also had to have good listening, reading and record keeping skills.

We had only 220 Dataphone circuits in 1967.  Not counting the Dial TWX  
machines that are included in the 600 below...

486 Teletype machines we maintained in the Chicago suburban area were  
all fed with -130 vdc and 62.5 milliamps.
Our TTS-28 test sets had a red mark on the face of the dial for 62.5 ma.

Only 2 machines ran on 260 vdc 62.5 milliamp loops at any one time.  
These -130/+130 were temporary until we
could get a current source closer to the machines. These 260 volt  
circuits required wave-shapers to get a square
enough signal to get a decent range on the selector.  (A wave-shaper  
is a multi-tap set of coils to balance out the
ong capacitance loop.)

4 machines ran on 130 subsets (similar to 43A carrier) with very short  
local 120 volt 62.5 ma loops.
110 TWX machines had 101B and 101C Datasets which used Selector  
Magnetic Driver (SMD) cards.  All of our TWX
machines had private line voice grade circuits to the TWX regional  
switching center in the Chicago-Congress CO.

I went to Teletype Corp School in the Corn Products Building on Wells  
Street in Chicago.
That is the only place I ever saw Model 10, 12 and 14 machines that  
were displayed from the Teletype Corp Museum.

During this time we had only 6 Model 15s in service, 6 model 19s, and  
no model 14s, nor 31s, nor 26s.
We maintained several different Teletype Switching Systems including  
81D1, 82B3, 83B1, 8A1, and one SCATS for
a pipeline company.

We also maintained about 12 or so BRPE Punch units used in central  
offices.  We had Model 33s and 35s but no M32s.
As time went on we maintained many Type 2 and Type 5 Dataspeed Senders  
and Receivers.  We had 1 Type 4 Sender.

The last machines I was trained on were the 4210 Mag Tape Terminal and  
Model 37 ASR. These schools were held in
the new Teletype Training Center located in the Morton Salt Building  
on Randolph St. just West of the Chicago River.

Memories, memories...

Don
K9TTY