Released under the John F. Kennedy Assassination Records Collection Act of 1992 (44 USC 2107 Hote}. DATE: 11-14-2017 JFK Assassination System Date: 6/11/201 Identification Form Agency Information AGENCY: _ FBI RECORD NUMBER: — 124-10210-10189 RECORD SERIES: HQ AGENCY FILE NUMBER:  92-2781-1ST NR 350 7 Document Information ORIGINATOR: FBI 7 FROM: SAC, TP TO: DIRECTOR, FBI . ‘ TITLE : DATE: — 10/30/1961 “PAGES: 3 SUBJECTS : LST, TESUR DOCUMENT TYPE: PAPER, TEXTUAL DOCUMENT CLASSIFICATION: — Secret RESTRICTIONS: 1B CURRENT STATUS: — Redact DATE OF LAST REVIEW: 10/08/1998 - ’ OPENING CRITERIA: INDEFINITE f COMMENTS : ° v eee v9.1 44 Docld: 32292791353 Page 1 7
' Released under the John F. Kennedy Assassination Records Collection DATE: Act of 1992 (44 USC 2407 Hotey” 14-14-2017 OPTIONAL FORM NO. 10 wel C spent Memorandum U NITED STATES GOV: ro Director, FBI (80-760). fi From: N/Sac, Tampa [ (66-231) Db) aa at i ; it } ! SANTO TRAFFICANTE, JR., aka | SUBJECT: AR ReBuairtel 10/11/61, requesting that Tampa. Office obtain certain technical information prior to the faltering of type 80 telephones for possible SPMT] use It is noted that: this technique - Fey considered aS was suggested by previous Bureau airtel dated 9/26/61 and captioned as above, contained in Bufile 92-2781. Mx. DONALD WITHERS, General Plant Training Supervisor, General Telephone Company of Florida, furnished information included in the following: . The General Telephone Company of Florida does not generally use the tip and ring party type of ringing on party lines. They use bridged ringing with harmonic ringers using some or all of the below-listed frequencies: ALL INFORMAUONASONTAINED ~ Oni 16,.6~cycle harm9nic HERES UNOS 20-cycle harmonic or decimonic 25-cycle harmonic 30-cycle harmonic or decimonic 33.3-cycle harmonic ALL (fFosatiog ony .40-cycle decimonic HES 3 TARE | 42-cycle harmonic EXE ERE SHOWN 50-cycle harmonic onl PTHERWISE a SO0-cycle decimonic pO Ooo fF - - ‘54-cycle harmonic |Z2 -~G7k/ — 60-cycle decimonic aq t RECORDED 66-cycle harmonic 102 nov "Sosy : 66-6-cycle harmonic US On party lines having more than five parties. ai vided and tip ringing and dividéedsAring ringing could be used. This,,. however, would not be the situation on the Four-party or private ‘ee as would be encountered in this manne is 3 phe , Opinion , ys Mo wephy Qe mo" / gs is 5 ody set ears ta ~KH (3) NOV 1% 1961: "i | Docld: 32292913 Page 2?
) Released under the John F. Kennedy Assassination Records Collection Act of 1992 (44 usc SIT H DATE: “1f-14- -2017. ‘ . ; ber a “ mfeslQy vai bani, of Mr. WITHERS that a 3, 000- ohm resistor across the subscriber's. line would possibly tend to change the ringer frequency causing - possible failure to ring or an alteration of the sound of. the bell due to the lack of full ringing current. ; The "Line Compensating Rheostat" in the manually ~, adjusted loop compensator circuit would normally be set at O on a long cable loop such as in the telephone installation serving _the subscriber in this case. With the "loop compensator" set ~ at zero, the 400-ohm resistor is in effect shorted out. When set in this zero position it is noted that the switch element of the "loop compensator" adds a capacitor and resistor to the sidetone balancing impedence to more nearly match the capacitive impedence of the long cable loop. In installations where it is desirable to set the compensating rheostat at zero © but where the sidetone balancing network is not desired in the circuit, it is the practice to set the "loop compensator" just off zero where the 400-ohm resistance would be shorted out but just short of the point where the switch connects the. sidetone balancing network. It is felt that a short could be. placed across the "400~ohm resistor of the loop compensator" to prevent the rheostat from developing an open or becoming. ‘noisy without effecting the operation of the instrument. : The sidetone balancing network coujd then be either, in the = « © circuit if the "loop compensator" is set at zero, or out of the circuit on any other setting. On a party line this would also apply as "loop compensators" are set without regard for other telephones in the circuit. The loop compensation rheostat - ghould be set in such a position as to cause 60 milliamperes of current to flow in the line. eee ann oe eee Mr. WITHERS has advised that in his opinion a 3,000-ohm resistance across the subscriber's line could cause an echo ° effect and would make a noticeable difference in transmission level. It could possibly cause central office equipment to reject the line indicating a trouble condition. A Vincent Rare Gas Relay is sometimes used across : a eubscriber's line to eliminate interference from nearby . power lines. t is not believed that this: will have any effect upon an[Sputfinstaiiation, Docld: 32292791353 Page 3
‘Released under the John F. Xennedy Assassination. Records Collection Act. of 1992 (44 USC C 210% Hoty.” DARE: aaa 14-2017 DO . - . ; . . ; \ “ a ° wet : : : 7 ; ; _ th fEe-20 1G (wy * mC ENTIAL Telephone service is presently being installed in ‘the home of subscriber JOE DIEZ, where the;altered telephone using the 3,000-cohm resistor would ‘be. used. The actual loop resistance of this line is being méasured and a simulated ‘circuit will be set up to test theories described above. -The Bureau will be advised of the result of these tests. | Docld: 32292913 Page 4