FSC-0016

                       FidoNet mail session startup
                                    by
                          Bob Hartman, 1:132/101

     Presently, FSC001  contains no  provisions for  what actually  happens
when a  call is received.  All it says is that the baud rate is determined,
and a netmail session starts.  Currently, this is one of the most difficult
sections of  a netmail program to get working.  All programs have different
timeouts, different ways of determining baud rates, not to mention the fact
that MNP  modems talking  to non-MNP  modems can cause problems.  For these
reasons, I  propose the following "standard" for netmail programs that deal
with the beginning of a netmail session:

1. When  carrier is  detected, all  input should be deleted by the receiver
     for a period of 2 seconds (I would even be comfortable with 5 seconds,
     but it  makes human  callers a  bit unhappy).   This  enables most MNP
     modems to  send their  string of  MNP "garbage" and not cause spurious
     characters to impact the netmail startup logic.

2. The  sender should  send ONLY  carriage return  and space  characters as
     "whacking return"  until the receiver acknowledges by sending a string
     containing a carriage return or space character.

3. The  sender should whack return at the rate of one character per second.
     This gives Fido 11w and other implementations time to purge buffers if
     line noise  is received  which would  screw up the baud rate detection
     logic.

4. After  recognizing the  "whack"  of  the  sender,  the  receiver  should
     disregard all characters except the following:

     TSYNC -  start of  an FSC001  session (a  delay of at least one second
          should appear  here so  the sender  can recognize  a valid  NAK -
          otherwise, it  could still  be the  banner file being displayed).
          WaZOO mailers  should disregard the first TSYNC in the hopes that
          a YooHoo  will appear.   If  a YooHoo  is not  received within  2
          seconds, or  a second  TSYNC appears, an FSC001 session should be
          started.

     YooHoo - signals the start of a WaZOO netmail session.  FSC001 mailers
          should just ignore this character as noise.

     Carriage return,  space -  Send  message  containing  carriage  return
          and/or space.   The  sender may  have missed  it the  first  time
          around and is still "whacking return".

     Line feed  - This  is probably a user, and a message explaining things
          to him/her should be sent out.

     Escape - This character is currently used by at least one front end as
          a quick  method for users to enter the BBS.  If received in "mail
          mode", it  should always  be ignored.    (I  propose  this  as  a
          "standard" so that all front-ends can use this feature.  If it is
          not  standardized  now,  all  front-ends  could  conceivably  use
          different characters  and  further  muddle  the  picture  when  a
          netmail session is starting.)

5. After  the sender has started sending TSYNC and/or YooHoo, the responses
     must be  looked at  very carefully.   A  line with  no activity for at
     least .5  seconds must  be seen.   Otherwise,  it is  possible that  a
     banner file is still being displayed and a 'C' is meaningless.

     If  all   FidoNet  compatible  mail  programs  were  to  follow  these
conventions, I  believe that  the start  of a netmail session would be much
more reliable  than it  is right  now.  Too often we see front end packages
fall through  to the  underlying BBS because of MNP negotiation, or one end
taking longer than the other to give a connect message.