Configure Terminal Switch GS1900

Hello,


I have a gs1900 in use.
Unfortunately I can't get into the config terminal mode via SSH.
The question now is what am I doing wrong?


regards
Thomas


GS1900#
  clear       Clear configuration
  copy        Copy from one file to another
  debug       Debug Options
  end         End current mode and change to enable mode
  exit        Exit current mode and down to previous mode
  no          Negate command
  ping        Send ICMP ECHO_REQUEST to network hosts
  show        Show running system information
  traceroute  Trace route to network hosts
GS1900# conf t
Unknown command
GS1900# configure Terminal
Unknown command
GS1900#