Int 14 Fn 07  - Telapi - Read Block                                        [N]

   AH = 07h
   CX = length of buffer in bytes
   DX = port number
   ES:DI -> buffer for data

Return: AX > 0000h number of characters actually read
   AX = 0000h host has closed connection
   AX < 0000h error code (see #0323)
   CX = ???

Note:  translates CRLF into local EOL if the connection is in ASCII mode,
     negotiates various Telnet options, and immediately executes several
     different Telnet action commands

See Also: AH=06h"TelAPI",AH=E0h"TelAPI",AH=E2h"TelAPI"