Position  34  through  end-of-routing  signal  (start- of-routing  signal and addressees)   —The  positions reserved for routing are made up of two sections: start- of-routing  signal  and  the  addressees’  routing  indicators. The start-of-routing signal consists of two consecutive hyphens and will always precede the first addressee routing indicator. Addressee routing indicators are listed  immediately  following  the  start-of-routing  signal. A  message  can  have  a  maximum  of  500  routing indicators  in  these  positions.  If  a  message  contains  501 or more routing indicators, the message will require two separate   transmission.   In   this   case,   all   routing indicators that have the same first four letters should be in one transmission End-of-Routing Signal  —The  end-of-routing signal consists of a period (.) and is inserted in the position immediately following the last addressee routing  indicator. SECURITY  WARNING  (FORMAT  LINE 4). —A security warning is the first component of format line 4. The appropriate operating signal (ZNR or ZNY) will always be followed by a classification character repeated five times. The operating signal and classification characters are as follows: ZNR UUUUU —For off-line encrypted messages and classified messages transmitted in the clear; ZNY EEEEE  —For unclassified EFTO messages; and ZNY,   followed   by   CCCCC,   SSSSS,   or TTTTT —For Confidential, Secret, or Top Secret messages,   respectively. For SPECAT and SPECAT  SIOP-ESI  messages, the five redundant security characters are followed by an oblique (/)   AAAAA for SIOP-ESI or BBBBB for all other SPECAT messages. For example, format line 4 for a Top Secret SPECAT message would be: ZNY  TTTTT/AAAAA(2CR, 1LF) END OF MESSAGE  (EOM) (FORMAT LINES 15 AND 16). —Format line 15 is the EOM validation line that is used to inhibit suspected straggler messages. Format line 15 consists of the SSN in format line 2 preceded by the number sign (#). Format line 16 consists of the EOM functions.  The EOM functions consist of normal teleprinter ending procedure when five-level  Baudot  code  is  used  (2CR,  8LF,  4Ns, 12LTRS).  However,  for  ASCII,  12  delete  functions  are used (12DEL). The EOM for the message with format line 2 shown in figure 1-2 would be as follows: Format lines 1, 2, 4, and 5 must all be accurately prepared.  Backspacing,  lettering  out,  double-spacing, or  using  two  or  more  FIGURES  and  LETTERS functions in sequence will cause the ASC to reject the message  during  attempted  transmission  from  the originating station. The EOM validation appearing in format line 15 and the EOM function in format line 16 must be prepared in uninterrupted sequence, be letter- perfect, and be without corrections. General  Teleprinter  Rules A  leader  must  precede  the  header  to  ensure acceptance and transmission of the first character of the message  header.  The  leader  for  the  five-level  Baudot code (most common) consists of at least six blanks and six letter functions.  The leader for the  ASCII (eight- level Baudot code) consists of at least six nulls and six delete functions.  This will ensure acceptance and transmission of the first character of the message header. When a message is assigned dual precedence, the higher precedence is shown in format line 2 (position 1). Both precedences are shown in format line 5. Communications  personnel  of  tributary  stations must ensure that a record is made of the time of file (TOF) and the time available for delivery (TAD). These times  are  used  to  determine  message-processing  times. Message Lengths Messages cannot exceed more than 20 lines of heading  and  text,  beginning  with  format  line  5. Messages  that  exceed  the  20-line  limit  must  be  divided into pages for transmission.  The second and succeeding pages of a message are identified by the page number, the  routing indicator of the station of origin, and the SSN. The security classification of classified messages follows the page identification.  After the first letter of the classification, you must separate each letter by one space from the previous letter. For example: On unclassified messages, "UNCLAS" is placed after the page identification with no spaces separating the letters. 1-9