RFSC   SEND Patch Panels In  the  following  paragraphs,  we  will  discuss  the equipment shown in the RFCS transmit (send) system in figure 2-18. Teletypewriter Sets The Model 28 family and the AN/UGC-143 series are   the   two   tty   sets   currently   used   by   the   Navy. Although  the  AN/UGC-143  is  not  shown  in  figure 2-17, we will discuss its characteristics later. There are several tty sets included in the Model 28 family with varying weights and sizes. They feature high operating speeds, quiet operation, and are particularly suited for shipboard   use   under   the   severe   conditions   of   roll, vibration, and shock. Model 28 tty’s may be composed of the following components, depending upon their specific function: a cabinet,   keyboard,   page   printer,   typing   perforator, transmitter  distributor,  typing  reperforator,  power distribution panels, and power supply. All  equipment  components  are  housed  in  the cabinet.   Transmissions   are   initiated   through   the keyboard  or  transmitter  distributor.  Received  signals are   printed   on   the   page   printer.   Monitored transmissions can also be printed on the page printer. The  typing  perforator  and  reperforator  are  used  for preparing   tapes   that   can   be   stored   for   future transmission through the transmitter distributor. The AN/UGC-143A(V) is also known as the Navy Standard   Teleprinter   (NST)   and   has   the   following characteristics: Fully  automated Accepts Baudot code or ASCII Bulk storage unit contains tape drives similar to those found in the AN/USH-26 Can   be   configured   to   interface   with   Navy standard  personal  computers Fully compatible with current crypto devices Capable of supporting paper tape operations Tty   panels   SB-1203/UG   and   SB-1210/UGQ are   used   for   interconnection   and   transfer   of shipboard   tty   equipment.   The   SB-1203/UG   is   a general-use  panel  and  the  SB-1210/UGQ  is  intended for  use  with  crypto.  In  addition,  tty  panels  furnish  a central  point  for  connecting  the  dc  supply  into  the teletypewriter  circuits.  So,  one  source  of  supply  can be   used   for   all   the   circuits   passing   through   a particular   panel. One   procedural   note:   Anyone   patching   or unpatching  circuits  from  a  tty  panel  must be sure to pull   the   plug   from   the   looping   jack   before removing  the  other  plug  from  the  set  (machine) jack.   Pulling   the   set   jack   first   interrupts   all   tty message   traffic   on   that   channel.   I T    A L S O PRODUCES  A  DANGEROUS  DC  VOLTAGE ON   THE   EXPOSED   PLUG! Cryptographic  Equipment Cryptographic  equipment  is  used  to  encode  and decode messages that require security handling. To do this, the crypto equipment must be compatible on both the transmit and receive ends. Remote Transmitter Control The  remote  transmitter  control  unit  is  mounted close   to   the   tty   keyboard,   and   permits   remote control  of  the  transmitter.  For  RFCS  operation,  the operator   sets   the   three-position   rotary   switch   to CFS   SEND   to   transmit   and   CFS   REC   for   receiv- ing.   The   TONE   S/R   position   is   used   for   AFTS transmit   and   receive. Transmitter Switchboard The  SB-863/SRT  switchboard  is  used  in  this system to connect the remote transmitter control to the transmitter to be used. Transmitter The   transmitter   is   used   to   transmit   the   RFCS signal.  It  is  important  that  the  operator  tune  the transmitter to the proper frequency. 2-20