866VAE-K9 Modem/AUX and rev. telnet Problem

Question

Hi Everyone,
I am currently observing some strange behavior of 866VAE-K9 router which might be a bug or my mistake, so I would very much appreciate your suggestions...
The 866VAE-K9 router has a single physical AUX/CON port.
The documentation states that in order to use AUX with a modem
one has to:
line con 0
 modem enable
If I do this, some process starts on the line 1 and prevents
using of chat scripts and reverse telnet:
 start-chat Dialout1 aux 0
% Chat script can not be run on line running other process
telnet 192.168.10.1 2001
Trying 192.168.10.1, 2001 ...
% Connection refused by remote host
If I clear line 1, and immediately after that start a chat script,
then it works (telnet hangs on at "asserting DTR"), but if I wait for
several seconds the line 1 becomes busy again...
Your suggestions/ideas are very appreciated!
sh line
   Tty Typ     Tx/Rx    A Modem  Roty AccO AccI   Uses   Noise  Overruns   Int
      0 CTY              -    -      -    -    -      0       0     0/0       -
*     1 AUX   9600/9600  -    -      -    -    -      1       0     0/0       -
*     2 VTY              -    -      -    -    -      1       0     0/0       -
*     3 VTY              -    -      -    -    -      2       0     0/0       -
      4 VTY              -    -      -    -    -      0       0     0/0       -
      5 VTY              -    -      -    -    -      0       0     0/0       -
      6 VTY              -    -      -    -    -      0       0     0/0       -
Mainz(config-line)#                                 
Mainz(config-line)#
Mainz(config-line)#do sh users
    Line       User       Host(s)              Idle       Location
   1 aux 0                idle                 00:01:05 192.168.10.1
*  2 vty 0     jip        idle                 00:00:00 192.168.10.10
   3 vty 1     jip        192.168.10.1         00:01:05 192.168.10.10
  Interface    User               Mode         Idle     Peer Address

Answer 1

forgot the config:
line con 0
 exec-timeout 0 0
 login local
 modem enable
 escape-character BREAK
 stopbits 1
line aux 0
 exec-timeout 0 0
 modem InOut
 no exec
 transport input all
 escape-character BREAK
 stopbits 1
 speed 115200
 flowcontrol hardware