XMT - Intercomputer Communications Task CHAPTER 1 Overview XMT is a utility task at the Engineering Work Station (EWS) which provides a convenient means for data transfer between the EWS and any other computer system that is acces- sible with a standard terminal by either hard-wired lines or by dial-up modem. XMT makes the user terminal appear as though it were a typical "teletype" to the remote computer system. Data transfer is performed by producing textual output from the remote computer (e.g., program listings, computer runs, etc.) and, through XMT, routing that text to a disk file at the EWS. The reverse path takes a file at the EWS and "types" it to the remote. CHAPTER 2 Using XMT To run XMT, type "XMT" followed by a carriage-return. XMT then prints the message "Terminal Transmission Program" and asks you to enter the number of the terminal that you will connect to the remote computer. Usually this will be TT3: or TT12:. If these terminals are connected to a dial-up modem you must now dial the remote computer before responding to the question by XMT. If the terminal is hardwired to the remote system, or when you have made the connection to the remote via modem, enter the terminal number and hit carriage-return. XMT is now running with several defaults in effect: unduplexed operation (everything you type is NOT echoed on your terminal unless the remote computer echoes each char- acter for you), no parity, control characters can be rede- fined (and several of them are redefined - see the appen- dix), and file transfer modes are ASCII format. These set- tings can be changed dynamically by the user to tailor XMT's characteristics to ease communication with other computers. To leave XMT, type CTRL/C twice (CTRL/C is typed by holding down the CTRL key and typing C), or by typing CTRL/C followed by X (eXit). CHAPTER 3 XMT Options To change any of the program settings/options, type CTRL/C followed by the upper case character signifying the setting/option desired. Below is a table of options and their corresponding definitions: NOTE Do NOT type a carriage-return to enter or execute any of these commands. Typing the single character of the com- mand is all that you need to execute that option. A - Changes the file transfer mode to ASCII if in the binary mode, or changes the file transfer mode to binary if already in the ASCII mode. B - Sets the BREAK (logical spacing) key definition to some keyboard character which, when depressed, creates a 'BREAK' condition to occur just like the 'BREAK' key on a teletype. C - Enter/exit Copy mode; i.e., when receiving a file from the remote in ASCII mode, all characters typed at the keyboard are copied to the output file when also in Copy mode. D - Set the length of delay that XMT should wait after receiving a prompt character before sending the next line of data from a disk file at the EWS. The delay can range from 0 to 99, where 0 corres- ponds to no delay and 99 corresponds to 99 clock ticks (approximately 1 2/3 seconds). If the length of the delay is a single digit, typing a carriage-return after typing the digit will be suf- ficient to enter the delay. You may also enter a XMT Options PAGE 3-2 single digit for the delay by preceeding it with a zero. You cannot enter a delay of more than two digits. Any characters entered other than 0 through 9 will cause the default delay of 20 to be used and no error message will be given. E - Enter/exit Echo mode; i.e., when receiving or transmitting a file all input/output from/to the EWS disk is printed on the user terminal. This mode is useful when you wish to see the effects of transmission in progress. In general, this mode should only be used when you are logged onto a high-speed terminal or when the amount of printing is less than 2 full pages (at 1200 baud) or inde- finitely (at 300 baud or less). F - Receive a file From the remote. A short status of the applicable options in effect is printed be- fore a file specification is requested. The file specification is 29 or fewer characters and follows the system standard conventions for files. Entering a name of less than 29 characters requires a carriage-return to enter the filename. The RU- BOUT or DELETE keys can be used to edit out any er- rors made in typing the file spec. Entry of a null, or empty, filename will allow you to exit the F option without sending any data or creating any files. Any previous execution of the F option that was not terminated by either the O option or by ex- itting XMT is automatically terminated prior to the printing of the short options-in-effect summary. H - Prints a very brief Help summary of the purpose of each option. I - Terminates reading input from a EWS disk file if such a file transfer was taking place. The mes- sage "Transmission Complete" will be printed if a file transfer is terminated, otherwise no action is taken. This option is useful in aborting the transmission of data to the remote if problems in communication arise. O - The O option performs the same function for terminating a file receive operation (Output to the EWS disk) that the I option performs on file transmit operations (Input from the EWS disk). This option is the only means, other than by exit- ting XMT or by starting another file receive opera- tion, of signalling the end of a receive operation to XMT. The message "Receive complete" prints when a receive operation is terminated. XMT Options PAGE 3-3 P - Change transmit file mode from Prompted mode to Promptless, and vice-versa. A message is printed indicating which mode is in effect. When changing to prompted mode you are asked which character sent by the remote computer system should be used as the prompting character. Type the prompting character and XMT will, during a file transmit operation, wait for this character to be received from the re- mote computer before sending the next line of in- formation to the remote. Note that XMT will send the first line of input to the remote computer without waiting for the prompt, but all other lines of input will wait for a prompt to be received be- fore they will be sent. R - Redefine/don't redefine control characters. This option enables and disables the user-defined translation table for control characters as des- cribed under the "^" option. A message is printed which mode is in effect. When in "Redefine mode" XMT will use a translation table to convert any re- defined control characters to some other control character so as to be able to "type" reserved con- trol characters to the remote computer. Examples of reserved control characters are CTRL/C, CTRL/O, CTRL/S, CTRL/Q, etc. "Not redefined mode" disables this translation, but the translation table is not destroyed. S - Prints a Status of the options in effect for XMT. The status report includes information about parity, ASCII or binary modes, information about file transfer operations, and prints the definition of the BREAK character, if any. T - Starts a file Transmit operation. This option is very similar to the F option except in the di- rection of data transfer. A check is made as to whether or not XMT was in the midst of a previously started file transmit operation, and if so, that transmit operation is terminated. A short status of file transmit options-in-effect is printed be- fore you are requested to type in the name of the file you wish to transfer to the remote system. If you just type a carriage-return, XMT simply returns without initiating a file transfer. Otherwise you must enter a file name in the standard system for- mat. If the name of the file you enter does exist on disk a message is printed indicating that the file is not found and no transfer operation is ini- tiated. Otherwise a file transfer is initiated which can be terminated by 1) exitting XMT, 2) using the I option, 3) using the T option again and XMT Options PAGE 3-4 entering a carriage-return for the name, or by 4) reaching the end of the input file. The message "Transmission complete" is printed when the transfer operation is completed (or terminated). U - Unduplex or duplex the XMT program. In the Un- duplexed mode characters typed on the terminal are not echoed to the terminal unless the remote com- puter performs the echoing. This mode is useful when communicating to computer systems as other EWS's. For communication with systems such as TSO, however, the Duplexed mode is required if you wish to see the characters that you type. X - EXit XMT. All file transfers, if any, are ter- minated and control is returned to the RSX-11M Exe- cutive. 8 - Enter 8-bit ASCII mode and exit 7-bit ASCII, or leave 8-bit ASCII and enter 7-bit ASCII and be asked what parity you desire. This mode allows you to determine whether or not the information you transmit and receive will be full 8-bit ASCII or 7-bit ASCII with software generated even, odd, mark, or no parity. Some computer systems require specific parity settings, but other EWS's and TSO don't care. ^ - Allows you to redefine a control character as a different control character. This allows you to use some otherwise reserved control characters, such as CTRL/C, and allow you to send these char- acters to the remote system. You will be asked to type two characters. The first character you type will be the redefined character and the second character you type will be the definition. To enter either of these characters may, and sometimes must, enter the upper-case equivalent of the con- trol character. The characters you type are auto- matically converted to the proper control character and their upper-case equivalent is printed after you type the character. For example, you wish to use the character CTRL/W to signal when you transmit a CTRL/C. Type the ^ option, the letter W, and the letter C and the redefinition has been set. Assuming that XMT is in "Redefine mode", every time you type a CTRL/W a CTRL/C is actually sent to the remote system. If you wish to change a definition, simply redefine it in the manner given above. CHAPTER 4 Summary of Capabilities 1. Full or half duplex operation 2. Disk file transmit and receive 3. Prompt character checking and delay 4. Optional echoing of files during transmission and reception 5. A short help message summary 6. The ability to transmit a file while also receiving another file 7. The ability to transfer files using a full 8 bits 8. The capability of transferring files with or with- out prompted handshaking 9. The option of preventing everything entered at the user terminal from being copied to an output disk file during a receive operation 10. The ability to create a 'BREAK', or logical spac- ing, condition so as to be able to interrupt remote devices such as TSO 11. The capability of defining almost any keyboard character to be used to signal when a BREAK was de- sired 12. The ability to perform translations of control characters entered at the user terminal to char- acters not normally able to be entered without in- terception by RSX-11M 13. The ability to turn on and off the control char- acter translation without losing the previous de- finitions Summary of Capabilities PAGE 4-2 14. The inclusion of a "status" subroutine which en- ables the user to see what parameters are currently in effect for the program 15. The ability to set the mode of parity (even, odd, mark, or none) to be used when transmitting each character to the remote while the 7-bit character mode is in effect. APPENDIX A XMT Default Control Character Definitions Typed Character Resulting Character ctrl/A ctrl/S ctrl/B ctrl/C ctrl/P ctrl/O ctrl/W ctrl/Q ctrl/X ctrl/Z