Thomas,

Welcome to Greenkeys and the world of mechanical digital communications!

The Teletype Corp. Model 15 used both 120 VDC and 120 VAC, so to keep them apart, the table was designed with different types of plugs. You may want to just ignore the interconnect box under the table and wire things directly. A schematic of box enclosed - should be similar to what you have.   For the motor, you can just use a standard 120 VAC, 3-prong (grounded) plug, wired to terminals 21 & 23 on the terminal block.

Electrically, the keyboard consists of 6 sets of contacts (bits 1-5, plus the STOP contact), all in parallel. In standby mode, the STOP contacts will be closed.   

Electrically, the printer consists of an electromagnet, known as the "Selector Magnet." This electromagnet is made up of two windings or coils, usually wired in parallel (60 ma. loop). It can also be wired in series (20 ma. loop).   

Normally, the keyboard and selector magnet of one unit is wired in series with the keyboard and selector magnet of a second unit, with a current limited power supply providing the 60 (or 20) ma current.  This is know as a "current loop" and is the same as was used with telegraph equipment.  See  "54 TTY loop" enclosed. Typically, for a 60 ma. loop, a supply of 120VDC with a 2000 ohm series, current limiting, resistor is used.

If you are mainly interested in connecting the M15 to a computer, there are 20 ma. loop to RS-232 adapters that you may be able to find.  But be aware that modern, USB, serial ports will not go slow enough for a teletypewriter! These machines only operate at 45 baud.       

Did you know that y our M15 can play music?
See https://www.youtube.com/watch?v=pDy60HDr558


Hope this helps,

Duncan Brown, K2OEQ
USASA    31J30

Antique Wireless Association
 Communication Technologies Museum
   Asst. Curator, Commercial Equipment
(also chief TTY op & repairman)

i-Telex: 212503

www.antiquewireless.org

AWA Youtube channel: https://www.youtube.com/channel/UCX55peBhzeX1qps_VYXdLBA

Virtual AWA Museum TTY Tour:  https://www.youtube.com/watch?v=TpB6jM90VV8



                                                                                                             

On 8/5/2026 6:40 PM, Thomas McCourt via GreenKeys wrote:
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