Testing 103.12.78.114:23...
  Recv: '\x01\x03\r\nWarning: Telnet is not a secure protocol, and it is recommended to use Stelnet.\r\n\r\n>>User name:'
  Echo: 'echo\x07 VANTAOK\r\n>>User password:'
  Which curl: '\r\n  Username or password invalid.\r\n>>User name:'
Testing 103.134.156.37:23...
  Recv: '\x01'
  Prompt: '\x01\x03\x18\x18\x1f\x1f"\x05\r\n\x1b[2J********************************************************************\r\n                  Optilink GEPON \r\n        Command Line Interface for EPON System         \r\n                 Hardwar'
  Echo: 'echoVANTAOK\r\nPassword:'
  Which curl: '\r\nUser name or password invalid!\r\n\r\nUsername:'
Testing 101.255.158.242:23...
  Recv: '****************************************************************\r\n**  GPON OLT Integrated Operating '
  Prompt: 'User Access Verification\r\n\r\n'
  Echo: '\x01\x03"\x1fUser name: echo VANTAOK\r\nPassword: '
  Which curl: '**********\r\n% Authentication fail, please entry again! \r\nUser name: '
Testing 103.138.60.243:23...
  Recv: '\x01'
  Prompt: '\x01\x03\x18\x18\x1f\x1f"\x05\r\n\x1b[2J********************************************************************\r\n        Command Line Interface for EPON System         \r\n                 Hardware Ver:  V1.0  \r\n                 So'
  Echo: 'echoVANTAOK\r\nPassword:'
  Which curl: '\r\nUser name or password invalid!\r\n\r\nUsername:'
Testing 103.157.104.175:23...
  Recv: '\r\n%connection refused by remote host!'
  Error: [Errno 32] Broken pipe