[GreenKeys] [External] Bunnell Pen Register

[Jones, Douglas W]

On Jan 29, 2020, at 11:07 PM, Harold Hallikainen wrote:

> A manual on the device is available at
> http://etler.com/docs/BSP/030/030-340-701_I2.pdf .

Interesting, reading this manual makes it clear that the register was turned over to someone:
  2.08(b) After turnover, it is recommended ...

And whoever it was turned over was responsible for both maintenance and keeping maintenance records before return to the phone co:
  2.03 ... During the period of installation a record shall be kept ... this record shall be turned over to the telephone company with the equipment ...

The machine is explicitly for recording telephone dial pulses:
  2.10 ... the register shall be capable of recording dial pulses ...
  3.10 M-2 ... Dial the digit zero.  The register should follow the dial pulses ...

These kinds of clauses in the notes suggest to me that this machine was understood to be routinely turned over to law enforcement when law enforcement asked to record the phone numbers dialed by some phone.  The date of the BSP, 1961, makes it pretty clear that these 19th-century-style pen registers remained in service right up until the introduction of touch-tone dialing, and possibly after.  Obviously, when touch-tone dialing came in, the phone company needed to offer an alternative way to record the number dialed when law enforcement demanded the use of a pen register.

		Doug Jones
		jones at cs.uiowa.edu