This is the exit to DOS information FeatherNet PRO! uses to maintain a caller's stats and the system's configuration upon exit to DOS when running a DOOR, during file transfers, or viewing some archives 

START POS   SAVED
& LENGTH     AS       DESCRIPTION OF DATA
---------  ------    --------------------------------------------
1, 2       ASCII     "-1" always used by FeatherNet PRO!
3, 2       ASCII     " 0" always used By FeatherNet PRO!
5, 2       ASCII     "-1" if page allowed or 0 if not.
7, 2       ASCII     User Number in Users file
9, 1       ASCII     "Y" if Expert or "N"if Not
10, 2      ASCII     "-1"  if  Error Correcting modem, "0" if not
12, 1      ASCII     "Y" if Graphics Mode or "N" if Not
13, 1      ASCII     "A" is always placed here by FeatherNet PRO!
14, 5      ASCII     The DTE speed or PC  to Modem baud rate
19, 5      ASCII     The connect baud rate:"300-38400" or "Local"
24, 2      MKI$      User's Record # in "USERS" file
26, 15     ASCII     User's FIRST Name padded with spaces
41, 12     ASCII     User's Password
53, 2      MKI$      Time user logged on in Mins: (60 x Hr)+Mins
55, 2      MKI$      User's Time on today in minutes
57, 5      ASCII     Time user logged on in HH:MM format. Ex: "12:30"
62, 2      MKI$      Time user allowed today in minutes
64, 2      ASCII     Daily D/L Limit from pwrd file
66, 1      Chr$      Conference the user has last joined
67, 5      Bitmap    Areas user has been in
72, 5      Bitmap    Areas user has scanned
77, 2      MKI$i     An mki$(0) used by FeatherNet PRO!
79, 2      MKI$      Currently a value of 0 is here (MKI$(0))
81, 4      ASCII     4 Spaces are placed here
85, 25     ASCII     User's Full name placed here.
110, 2     MKI$      Number of minutes user has left today
112, 1     chr$      Node user is on (actual character)
113, 5     ASCII     Scheduled EVENT time
118, 2     ASCII     A "-1" if EVENT is active or a " 0"
120, 2     ASCII     " 0" is Placed here by FeatherNet PRO!
122, 4     MKS$      Time of day in secs format when user is on
126, 1     ASCII     The Com port this node uses (0 - 8)
127, 2     ASCII     Flag to let FNET PRO! know type of file xfer
129, 1     CHAR      Ansi Detected Flag - Char[0] or Char[1]
130, 13    ASCII     Unused by FeatherNet PRO! - SPACE filled
143, 2     MKI$      Last Area User was in (0 - 32766 possible)
145        BITMAP    Not Currently Used by FeatherNet PRO!

Some BASIC functions:

CHR$
    Writes a character (8 bit value). One byte. 
MKI$
    Writes a short integer (16 bit value). Low byte then high byte. 
MKS$
    I didn't want to research this, and am writing four zeroes. Anyone know? 

Sources

• http://web.archive.org/web/20160325154954/http://goldfndr.home.mindspring.com/dropfile/pcboard.htm