access program to communicate with other computers via telephone line or serial device. When the first Macintosh was released, a program called MacTerminal was used to communicate with many computers, including the IBM PC. Dec Terminal was one of the first terminal programs for the popular Altair. The Win32 console on Windows does not emulate a physical terminal that supports escape sequences so SSH and Telnet programs (for logging in textually to remote computers) for Windows, including the Telnet program bundled with some versions of Windows, often incorporate their own code to process escape sequences. The terminal emulators on most Unix-like systems—such as, for example, gnome-terminal, qterminal, xterm, and Terminal.app—do emulate physical terminals including support for escape sequences; e.g., xterm can emulate the VT220 and Tektronix 4010 hardware terminals. Modes Terminals can operate in various modes, relating to when they send input typed by the user on the keyboard to the receiving system (whatever that may be): Character mode (a.k.a. character-at-a-time mode): In this mode, typed input is unbuffered and sent immediately to the receiving system. Line mode (a.k.a. line-at-a-time mode): In this mode, the terminal is buffered, provides a local line editing function, and sends an entire input line, after it has been locally edited, when the user presses an, e.g., , , key. A so-called "line mode terminal" operates solely in this mode. Block mode (a.k.a. screen-at-a-time mode): In this mode (also called block-oriented), the terminal is buffered and provides a local full-screen data function. The user can enter input into multiple fields in a form on the screen (defined to the terminal by the receiving system), moving the cursor around the screen using keys such as and the arrow keys and performing editing functions locally using , , and so forth. The terminal sends only the completed form, consisting of all the data entered on the screen, to the receiving system when the user presses an key. There is a distinction between the and the keys. In some multiple-mode terminals, that can switch between modes, pressing the key when not in block mode does not do the same thing as pressing the key. Whilst the key will cause an input line to be sent to the host in line-at-a-time mode, the key will rather cause the terminal to transmit the contents of the character row where the cursor is currently positioned to the host, host-issued prompts and