OTERM.DOC -- OTERM Terminal Simulator page 1 Copyright 1981, 1982 Michael M Rubenstein Version 4.00 (4 Oct 82) Credits. The modem protocol used for file transmission was developed by Ward Christensen. The modem protocol was extended to use the cyclical redundancy code by John Mahr. The subprogram to compute the cyclical redundancy code was written by Paul Hansknecht. The window manager is based on one written by Robert Lansdale. All four gentlemen have made their work freely available for noncommercial purposes. Ideas for many the features of OTERM have come from other terminal programs. The authors of these pro- grams must share the credit for OTERM. Most of OTERM is now written in C. It was compiled with the Software Toolworks C/80 compiler. A large number of people have offered suggestions and encouragement in developing this program. I thank all of them. The CompuServe CP/M Interest Group (CP-MIG) has been a valuable forum for discussion and a source of a great many ideas used in OTERM. OTERM.DOC -- OTERM Terminal Simulator page 2 Description. OTERM allows the user to communicate with time shar- ing services, computerized bulletin boards, and other computers. Special features of OTERM include: - a circular log of the session is kept. This log is under the control of the user. It may be browsed without exiting OTERM. - an optional warning is provided when the log is almost full. If the remote device supports it, transmission will be halted with a control S. If a file is being sent, the transmission is interrupted (it can be restarted.) - a file may be received without a protocol. If the remote supports ^s/^q to stop and start transmission, the file may be larger than main memory. - files may be sent to the remote computer without a special protocol for trans- mission. - any command which can be entered from the keyboard may also be entered from a file or from a function key. - file tranmission may be interrupted from the keyboard or from a command contained in the file. Transmission may be re- started without loss of data. - the Ward Christensen modem protocol is implemented. This allows error free com- munications with remote CP/Ms or other computers. - the CIS A protocol is implemented. This allows error free communications with CompuServe Information Services. - optionally lines may be wrapped so as to keep words on a single line (word wrap) - commands to OTERM are entered using function key 1. Help menus are available by entering ? in response to any prompt. - extended function keys are available. names of extended function keys may be up to 127 characters long and data sent by a function key may be up to 4094 characters. OTERM.DOC -- OTERM Terminal Simulator page 3 - the directory of a disk may be viewed from OTERM. - files may be deleted from OTERM. - files may be typed from OTERM. OTERM.DOC -- OTERM Terminal Simulator page 4 Limitations. OTERM will run only on an Osborne 1 computer. The revision level must be 1.2 or higher (the original rev A is no longer supported). No printer support is provided. OTERM is primarily designed for operator attended communications. There is no provision for auto answer. OTERM contains no provision for special modems. However with some modems, function keys can be used for autodialing or other functions. OTERM.DOC -- OTERM Terminal Simulator page 5 New features/corrections in version 4. Note: Version 4.00 is almost a complete rewrite of the program. Much of it has be rewritten in C. Browsing of the log has been implemented. The CIS A protocol has been implemented. Access to the directory , typing and deletion of files have been implemented. Extended function keys have been implemented. A window manager is now used to allow prompting for commands, display of messages from OTERM and of the log and directory. Escape sequences are not used except from a file. OTERM.DOC -- OTERM Terminal Simulator page 6 Using OTERM (summary). The modem should always be in full duplex mode for use with OTERM. Follow the modem manufacturer's and the Osborne instructions for connecting the modem. Note than almost all modem's will require that pin 2 on the modem be connected to pin 3 on the computer and pin 3 on the modem be connected to pin 2 on the computer. On exiting OTERM the RS232 interface will be reset to the same options as at entry. The setting of the rs232 rate and the line size on the disk have no effect on OTERM. OTERM always uses it's internal settings. As distributed, on startup OTERM is set to commun- icate with most time sharing services. The default characteristics may be changed temporarily or OTERM can easily be modified to start up with different characteristics. Establish communications following the modem manu- facturer's and the remote service's instructions. Commands to OTERM are preceded by function key 1 (control 1). Other function keys are used for OTERM functions. Several OTERM functions require significant time for disk access during which OTERM cannot check the modem. If the remote responds to control s to stop and control q to restart and OTERM is informed of this through the delay command, OTERM will stop the remote during these operations and no data will be lost. OTERM.DOC -- OTERM Terminal Simulator page 7 Function Keys. OTERM takes over the function keys. The function keys have the following meanings: ------------------------------------------- | 7 | 8 | 9 | | | | | | scroll up | scroll up | cancel | | half | full | file | | | | or fk | | | | | ------------------------------------------- | 4 | 5 | 6 | | | | | | scroll down | scroll down | cancel | | half | full | special | | | | display | | | | | ------------------------------------------- | 1 | 2 | 3 | | | | | | command | extended | standard | | | function | function | | | key | key | | | | | ------------------------------------------- A display similar to the above may be viewed by entering the fkhelp command. Use of function keys: Key Use --- ---------------------------------------------- 1 Signals OTERM that a command is to be entered. 2 Signals OTERM that an extended function key is to be entered. OTERM will prompt for the name of the function key. Extended function keys are installed in OTERM with the program OTSETUP. Note, that if the name of the function key is a single digit, the Osborne function key (installed with SETUP) will be used. This function may not be used while entering an OTERM command. 3 Signals OTERM that an Osborne function key is to be entered. OTERM does not prompt for the name of the function key, which must be a single digit or a single letter. If a single letter, the extended function key installed by OTSETUP will be used. This function may be used at any time, including while entering an OTERM command. OTERM.DOC -- OTERM Terminal Simulator page 8 4 Scrolls the special display down by half the size of the window. 5 Scrolls the special display down by the size of the window. 6 Clears special display (browse log, directory, typed file or the function key display). 7 Scrolls the special display up by half the size of the window. 8 Scrolls the special display up by the size of the window. 9 Cancels a protocol file transfer or halts transmission without protocol of a file. A transmission without protocol may be continued without loss. OTERM.DOC -- OTERM Terminal Simulator page 9 Extended function keys. Extended or Osborne function keys may be nested to a depth of 16. There is no checking for recursion. All function keys are canceled when a file read is started, but a file read may contain function keys. That is, if a function key contains a file read command, nothing in the function key will be processed after the command. Extended function keys are installed in OTERM with the program otsetup. See otsetup.doc for details. OTERM.DOC -- OTERM Terminal Simulator page 10 OTERM Commands. When function key 1 is entered, OTERM opens a window at the top of the screen and prompts for a command. You may then enter a command with or without argu- ments. In most cases, if no arguments are entered, OTERM will then prompt for them. In a few cases (e.g. dir) a default will be used. At any prompt you may enter a ? (followed by return) to see a list of possible operands or a description of the com- mand. In scanning commands, OTERM allows abbreviation to the minimum number of letters needed to identify the command or operand. Commands are checked in alphabetic order so the line command may be abbreviated "l", but the log command requires at least "lo". Commands and operands may be be entered in upper or lower case. In some cases (e.g. log) if no operand is entered, the current status is displayed. Examples: cmd: log on (will turn log on) cmd: log (will display log status and prompt for operands) cmd: quit (will exit OTERM) Several commands require the entry of a file name. OTERM uses a generalized file system which does not permit the use of "/" or "\" in a file name (of course the usual illegal characters are not allowed either). The slashes are used to set flags for the file system. The only flag which is of use in OTERM is \b, which causes an old file with the same name to be deleted, rather than renamed to .bak. Simply append this flag to the end of the name (after the extension) with no intervening spaces. The old file will only be deleted after the new file is successfully written. All file names may be entered in upper or lower case. A new disk may be mounted whenever there are no open files. A new disk may also be mounted on any drive except the default drive (the drive which is shown in the CP/M prompt, e.g. A>) whenever there are no files open on it. Remember, halting the reading of a file with function key 9 does not close the file. OTERM.DOC -- OTERM Terminal Simulator page 11 To modify OTERM to use new defaults, simply enter the desired commands, exit with the quit command, and save the program with the CP/M save command. Remember to check the current size of OTERM with stat before entering OTERM. The following sections describe in detail the OTERM commands. OTERM.DOC -- OTERM Terminal Simulator page 12 log command. A log of the session is kept in memory. As distri- buted, this log is enabled at start up. The log is circular; that is, when the log is filled, char- acters at the beginning are deleted as new char- acters are added. The size of the log depends on the version. The log is always cleared when OTERM is entered. If this command is entered without operands, the status of the log will be displayed. In full duplex mode, only characters received from the remote device are entered in the log. In half duplex mode all characters sent or received are entered. In host mode only characters sent are entered in the log. Since OTERM does not recognize deletion of char- acters or lines, it usually will be necessary to edit the log after writing it to disk to eliminate errors. The log may be edited with WordStar or ED. This is also useful for eliminating extraneous material from the log (e.g. commands or messages when a program source file is listed and logged.) The following operands are recognized: Operand Function ----------- ------------------------------------- clear Clears the log and starts entering data into it. endfile Stops automatic saving of the log. file Starts automatic saving of the log in a file. The file name is entered after the word "file". If not enter- ed, you will be prompted. This must be the last operand on the line. nowarn Turns off warning of log being almost full. off Turns off the log. Data currently in the log is not lost. on Turns on the log. Data currently in the log is not lost. warn Turns on warning of log being almost full. When the log is almost full, you will be informed with three bells and, if the remote responds to OTERM.DOC -- OTERM Terminal Simulator page 13 control s and control q (and OTERM is informed of this through the delay command) a control s will be sent. A control q will not be sent automati- cally. Warning is not effective if the log is being automatically saved. write Writes the current log to a file. The file name is be entered after the word "write". If not entered, you will be prompted. This must be the last operand on the line. A common (and the simplest) method of using the log is to simply ignore it until something is received which one wants to save. The log is then saved and later edited to eliminate unwanted material. OTERM.DOC -- OTERM Terminal Simulator page 14 browse command. The browse command is used to view the log. While active, the screen is split with the log displayed in the upper half and the terminal display in the lower. The scrolling function keys (4, 5, 7, and 8) are active while the log is being displayed. To turn off the log, use function key 6. The following operands are recognized: Operand Function ----------- ------------------------------------- down Followed by a number. Scrolls the log down the specified number of lines. Note: during scrolling, input from the remote cannot be completely processed and some data may be lost if the number of lines is larger than about 400 (at 300 baud). This must be the last operand on the line. end Starts browsing the log, showing the last data entered. start Starts browsing the log, showing the oldest data entered. up Followed by a number. Scrolls the log up the specified number of lines. Note: during scrolling, input from the remote cannot be completely pro- cessed and some data may be lost if the number of lines is larger than about 400 (at 300 baud). This must be the last operand on the line. If no operand is entered, "end" will be assumed. The display of the log will not be usable if the log does not contain line feeds. This will occur if line feeds are supplied on the console rather than by the remote service or by the transmission routines. OTERM.DOC -- OTERM Terminal Simulator page 15 cis command. Used to turn recognition of CompuServe A protocol on or off. Usually, recognition of CompuServe protocol will cause no problems, but there is a slight chance that some other service will send control sequences which make OTERM think it is engaged in an exchange with CompuServe. If this happens, turn off cis protocol. The possible operands are "on" or "off". If entered without operands, the status of cis mode will be displayed. CIS file transfers are initiated by the remote by sending a special sequence of characters. OTERM will notify you of the transfer. If it is an upload (transmission to the remote) the file size and estimated transmission time will be shown. The progress of the transmission will be displayed. Under this protocol blocks are variable length, but are normally either 128 characters or 256 char- acters. When sending, all blocks except, possibly, for the last are 256 characters. A file transfer may be cancelled with function key 9. The other system is notified of the cancel- lation. OTERM.DOC -- OTERM Terminal Simulator page 16 clear command. This command clears the screen. This is a local operation. Nothing is transmitted or logged. OTERM.DOC -- OTERM Terminal Simulator page 17 console command. The console command controls the display of informa- tion sent or received. It has no effect on the log or on the data transmitted: If entered without operands, the status of the con- sole will be displayed. The following operands are recognized: Operand Function ----------- ------------------------------------- autolf Treats a carriage return as the start of a new line (i.e displays as if it were a carriage return line feed). bsdel Deletes the previous character when a backspace is received. control Control characters are passed to the screen output routines and act as defined in the Osborne user's manual. ffclr Clears the screen when a form feed is received. ignorectl Control characters are ignored. maskctl Control characters are displayed as periods. noautolf Turns off autolf. A carriage return moves the cursor to the left, but does not start a new line. nobsdel Turns off bsdel. A backspace moves the cursor left one character, but does not delete the character. nowwrap Turns off word wrap. On reaching the end of the line on the screen, a new line is started immediately. showctl Control characters are displayed as "^" followed by a printing character. Rubout is displayed as "^?". wwrap Turns on word wrap. On reaching the end of a line, the line is broken at a word boundary. For the purposes of OTERM, a word boundary is a carriage return, line feed, space or horizontal tab. Note: word wrap is done at the end of the logical line OTERM.DOC -- OTERM Terminal Simulator page 18 as specified in the line command, not necessarily at the end of the physical screen. This option will probably not be too useful if the line size is set to greater than 52. The four options to control display of control codes apply to most nondisplayable codes. Carriage return, line feed, back space, and horizontal tab are not affected. Form feed is not affected if ffclr is on. Nulls are displayed only under showctl. Control z, which normally clears the screen on the Osborne, will be ignored if control and ffclr are both set on. OTERM.DOC -- OTERM Terminal Simulator page 19 delay command. When sending a file or a function key to a remote computer, it may be necessary to give the remote some time to process the data. This is accomplished with the delay command. Except for "usectls", the delay mode commands not meaningful except when a file or function key is being sent. If no operands are given, the delay status will be displayed. The following operands are recognized: Operand Function ----------- ------------------------------------- char Sets delay mode to character. When a delay is required, it will end whenever a character is received from the remote. This is the opposite of time. chdelay Causes a delay after each character sent. delay= Followed immediately by a digit (no space). Specifies the length of a character or line delay. If 0, the delay will always be until a character is received. delctls Causes transmission to stop when control s is received from the remote. Transmission will resume when a control q is received. lndelay Causes a delay after each line sent. nochdly Turns off chdelay. nodelctls Turns off delctls. nolndly Turns off lndelay. noprompt Turns off waiting for prompt after each line. nousectls Turns off usectls. prompt= Followed immediately (no space) by a character. After each line sent, OTERM will wait until the specifed character is received. A control OTERM.DOC -- OTERM Terminal Simulator page 20 character may be specified as ^ followed by a character (e.g. ^@ for NUL). time Causes character and line delays to last the specified time, regardless of characters received from the remote. The opposite of char. usectls Informs OTERM that the remote responds to control s to stop and control q to restart. This should be specified whenever possible to prevent loss of data on disk accesses. Use of delays for file transmission can be a bit tricky. Usually, a combination of line prompt and short character delay (1 or 2) works well if the remote provides a suitable prompt. In other cases fairly long (4-7) time delays may be needed. With half duplex systems, a line prompt or long (5-9) time delays will be needed. Some time sharing services (most using DEC equipment) will send a control s to stop transmission and a control q to restart. If delctls is set, the transmission will work well, but the display will probably be incoherrant if the remote is sending during the transmission. If a proper display is required, use a line prompt a character delay also. OTERM.DOC -- OTERM Terminal Simulator page 21 directory command. The directory of any disk may be viewed with the directory command. The only operand is the disk drive letter. If omitted the default disk is used. The directory is displayed in a window at the top of the screen. If there are more files than will fit in the window, the scrolling function keys (4, 5, 7, and 8) may be used to view the entire directory. The display is turned off with function key 6. OTERM.DOC -- OTERM Terminal Simulator page 22 diskspace command. The diskspace command may be used to display the disk space used and remaining on any drive. The only operand is the disk drive letter. If omitted, the default disk is used. OTERM.DOC -- OTERM Terminal Simulator page 23 erase command. The erase command is used to delete a file from a disk. It takes a single operand, the name of the file to be deleted. It is possible to delete a file which is being used, such as the file being typed or read. The erase command will be accepted, but actual deletion will be defered until the file is closed. If the file specified is the name of a temporary file generated for output (for the log file command), the erase command will be accepted, but will be ineffective. Such files are of the form TEMPnnnn.$$$, where nnnn are digits. OTERM.DOC -- OTERM Terminal Simulator page 24 file command. The file command is used to read a file as if it were typed at the console. The file may contain commands as an escape character followed by the digit for the function key desired. The responses to the prompts if any must follow in the file. All responses to prompts must be terminated by a car- riage return and line feed. An escape character may be sent by entering two escape characters in the file. This same technique is used to enter commands from function keys. Control characters may be ent- ered into the file, or may be specified as escape followed by a character (e.g. esc @ for NUL). Thus a file may contain either Osborne or extended function key calls. Reading of a file terminates any active function keys. If a file contains a command to read another file, control will pass to that file, but will not return at the end (files are chained not nested). Reading of a file may be temporarily halted by entering function key 9 from the console. It may be restarted with the file read command. If this command is entered without operands, the file status will be displayed. The following operands are recognized: Operand Function ----------- ------------------------------------- endfile Terminates reading of a file. The file is closed. halt Temporarily stops reading of a file. The file may be restarted with the read operand. This command is only useful if entered from a file. lf Allows transmission of line feeds contained in the file. Note: this also applies to function keys. nolf Ignores line feeds contained in the file. Note: this also applies to function keys. read Followed by the name of the file to be read. This must be the last operand on the line. If reading of a file was halted with function key 9 or by a file halt command, the file name may be * to continue the file. OTERM.DOC -- OTERM Terminal Simulator page 25 fkhelp command. Displays the standard OTERM function key usage. OTERM.DOC -- OTERM Terminal Simulator page 26 line command. Sets the logical line size to any length from 1 through 128. The only operand is the line size. NOTE: The line size affects only the display. The log and the transmission are not affected. If entered without an operand, the current line size will be displayed. OTERM.DOC -- OTERM Terminal Simulator page 27 modem command. Used to set the characteristics of the transmission. If entered without operands, the current transmis- sion status will be displayed. The following operands are recognized: Operand Function ----------- ------------------------------------- 300 Sets 300 baud. 1200 Sets 1200 baud. 7bits Sets 7 bits transmitted. 8bits Sets 8 bits transmitted. autolf Sets automatic transmission of line feed after carriage return. This option is usually required with host mode. even Sets even parity. full Sets full duplex operation. half Sets half duplex operation. host Sets host mode. All characters received are echoed back to the remote. Use host mode when the remote is a terminal (or a computer acting as a terminal). noautolf Turns off autolf noparity Sets no parity transmitted. odd Sets odd parity. rs232 Sets operation through the rs232 connector. Because of hardware re- strictions, this setting will send data to both the rs232 connector and the serial connector. serial Sets operation through the serial (modem) connector. Data is not sent to the rs232 connector. OTERM.DOC -- OTERM Terminal Simulator page 28 receive command and crcrecv command. The receive command is used to receive a file with the Ward Christensen modem protocol. This is compatible with the various versions of modem (single file transfers only), xmodem and yam. The only operand is the name of the file to be received (as it will appear on your system -- it need not be the same as on the remote). The crcrecv command is the same as the receive command, but crc checking will be used. This is superior to the standard checksum if the remote can handle it. The file transmission may be canceled with function key 9. The other end is not notified of the cancellation. If the other system sends a cancel (control x) in place of the normal block header, OTERM will inform you of this. This can be useful when one end wishes to halt a transmission. Don't cancel on the first one though, it may just be a transmission error. OTERM.DOC -- OTERM Terminal Simulator page 29 quit command. This command returns to CP/M. OTERM.DOC -- OTERM Terminal Simulator page 30 send command. The send command is used to send a file with the Ward Christensen modem protocol. This is compatible with the various versions of modem (single file transfers only), xmodem and yam. The only operand is the name of the file to be sent (as it appears on your system -- it need not be the same as on the remote). crc checking is implemented. In this protocol it is requested by the receiver. The file transmission may be canceled with function key 9. The other end is not notified of the cancellation. If the other system sends a cancel (control x) in place of the normal block header, OTERM will inform you of this. This can be useful when one end wishes to halt a transmission. Don't cancel on the first one though, it may just be a transmission error. OTERM.DOC -- OTERM Terminal Simulator page 31 type command Used to display a file. A single operand, an unambiguous file name, is accepted. The file is displayed as a secondary display. The scrolling function keys (4 and 5 only) are active. The file must be a standard CP/M text file, except that a file with lines terminated by carriage return, but no line feed, will be displayed properly. OTERM.DOC -- OTERM Terminal Simulator page 32 wait command This command delays transmission for from 1 through 60 seconds. This is sometimes useful in sending a file without protocol to allow for some action by the remote. The only operand is the number of seconds to wait. OTERM.DOC -- OTERM Terminal Simulator page 33 Protocol file transfers. This section contains information on using OTERM to send and receive files. The information on use of other programs is, of course, not to be taken as absolute. There are many different versions of other programs which will communicate with OTERM and details vary. When in doubt, check the documentation of the other program. Most rcpm's have help files or documentation files available. To communicate with another system, one of the systems must have an originate modem, the other an answer modem (not necessarily auto answer -- the term answer here refers only to the frequencies used). Most moderately priced to expensive modems can operate in either originate or answer mode. Transfers from OTERM to OTERM It is usually best to first establish communica- tions. One of the systems is set to host mode and auto line feed transmission (modem host autolf) and the other to full duplex (modem full). It is then possible to communicate through OTERM. Once commu- nications have been established, the receiver enters the crcrecv command and the sender enters the send command. The transfer will then begin. One may use the receive command, but the crcrecv command gives greater assurance of correct transfer at no measurable cost. Transfers with other systems The same method as for OTERM-OTERM transfers should be used, if possible. Some programs, however, do not allow establishing communications as a terminal first. In that case, once the modems have esta- blished carriers, enter the required commands. If the other system allows crc checking, it should be used. Some programs are set up for automatic selection of crc checking. If sending a file to such a program, issue the send command to OTERM before the other system issues the receive command. OTERM.DOC -- OTERM Terminal Simulator page 34 Receiving from an rcpm. Most rcpm's use the following method. Type (to the rcpm, not as an OTERM command) xmodem s followed by return. is the name of the file as it appears on the rcpm. The xmodem program will type a message telling you that it can transfer the file or that there is an error. Usually, if the file can be transferred it will tell you the size and the estimated transmission time. When the message is complete, enter the OTERM command crcrecv where is the file name you wish to use. Usually it should be the same as on the rcpm, except that files with type .OBJ should be received with type .COM. These are really COM files, but are put on the rcpm with a different type so you will not be able to run them. Usually, you cannot receive files with type .COM on the rcpm. A few systems do not support crc checking. In that case, use the receive command. Sending to an rcpm This is similar to receiving. The command for the rcpm is xmodem rc for sending with crc checking. If crc checking is not available, the command is xmodem r The OTERM command is send Rcpm's will not accept files with a type of .COM. Use the type .OBJ in the xmodem command (many systems will automatically change it if you forget.) Some systems will automatically put the file you send to a special area. Others ask that you put it in some special area yourself. A few don't care where you put it. OTERM.DOC -- OTERM Terminal Simulator page 35 Transferring files with CompuServe Make sure cis protocol is on in OTERM (cis on). You may generally leave it on. It will seldom do any harm. There are no OTERM commands directly associated with CompuServe file transfers. You enter commands to CompuServe, and the system sends the required instructions to OTERM. To send or receive a file from your user area, or from another user area which is accessable to you, enter the (CompuServe) command r xftran You will be prompted for details. To receive a file from access, enter the (CompuServe) command dow where is the name of the file you wish to receive. Again, you will be prompted for details. Display during transfers During the transfer, OTERM displays the block being sent or received and the number of retries. If a retry is required, OTERM displays the reason. Retries are made if either end discovers an error in the transmission. If there are a great number of retries required, the phone line is probably bad. A few retries are no cause for concern. In some cases transmission errors may cause the transmission to be halted. OTERM will always inform you of this, and if a file is being received will delete the file. In this case, an old file of the same name will be retained. OTERM.DOC -- OTERM Terminal Simulator page 36 Common problems. Protocol file transfers. The most common problem in making protocol transfers is failure to use a program in the remote which uses a compatible protocol or using the wrong protocol. OTERM can communicate with programs using the Ward Christensen modem protocol, with or without crc checking, or with programs using the CompuServe A protocol. Versions of modem (a terminal program) are available for most CP/M systems at no cost. Some versions (modem 7) also support a batch transmission protocol for sending multiple files. This batch protocol is not supported by OTERM. The modem protocol is also supported by xmodem (used by remote CP/M (rcpm) systems), by yam (available at no charge from CompuServe CP/M Interest Group (CP- MIG), or from many rcpm systems), and by a number of commercial terminal programs. The CompuServe A protocol is primarily useful for uploading and downloading from CompuServe. This protocol is controled by the remote (OTERM cannot act as host for this protocol). Programs are avail- able from CompuServe CP-MIG to allow CP/M systems to act as host, but it usually will be better to use the modem protocol. Double spacing Line feeds may be supplied by the remote or by OTERM or may be supplied on the screen only. If more than one source is supplying line feeds, the display will be double spaced. For most time sharing systems or bulletin boards, line feeds will be supplied by the remote and OTERM should be set to console noautolf modem noautolf file nolf When communicating with a terminal (or a terminal program) OTERM will usually have to supply line feeds and should be set to console noautolf modem autolf file nolf In this case, OTERM will usually be in host mode. OTERM.DOC -- OTERM Terminal Simulator page 37 Characters not displayed or Characters displayed twice In full duplex mode, characters typed are not shown on the screen and must be echoed by the "host". In half duplex mode, each side is responsible for displaying characters it sends, but most time sharing services and bulletin boards will supply "free" line feed. When communicating with a terminal, OTERM may act as the host. OTERM and the remote must be in agreement with the remote as to whether the transmission is full or half duplex. Most bulletin boards operate only in full duplex mode. Most time sharing systems may operate in either full or half duplex mode. Full duplex is generally best as the echo gives assurance that characters were received properly. A notable exception is that time sharing systems on IBM mainframes usually operate in half duplex mode only. If OTERM is in half duplex mode while the remote thinks it is host to full duplex, anything you type will be displayed twice. If OTERM is in full duplex, while the remote thinks it is in half duplex mode, nothing you type will be displayed. If both OTERM and the remote are acting as hosts to full duplex, a character will be repeated indefinitely. Unable to establish communications. This is usually due to incompatibility of the modems being used (there are two incompatible "standards" for 1200 baud modems. If you and the remote are using different standards, you will get nowhere.) or by incompatibility of the transmissions settings. The two sides should be in agreement as to data rate (OTERM supports 300 baud or 1200 baud), number of stop bits, number of data bits, and parity. Most systems will work with 8 data bits, 1 stop bit, no parity. Problems with nonprotocol file sending. A good deal of playing around may be necessary to get the transmission to work properly. If at all possible, a line prompt should be used. In other cases, it may be necessary to set the delay to time. When all else fails, try long time delays (5-9). The transmission will be painfully slow, but in most cases this will work. OTERM.DOC -- OTERM Terminal Simulator page 38 Remember that with nonprotocl transfers there is no error checking. Line noise may garble a character and the error will be undetected. Do not use nonprotocol transfers if the other system supports the modem or CIS protocol. OTERM.DOC -- OTERM Terminal Simulator page 39 Browse.................................. 12 Characters displayed twice.............. 33 Characters not displayed................ 33 Cis command............................. 13 Clear command........................... 14 Commands................................ 5 Common problems......................... 33 CompuServe A protocol................... 13 Console command......................... 15 Control q............................... 5 Control s............................... 5 Crcrecv command......................... 25 Credits................................. 1 Delay command........................... 17 Description............................. 2 Directory command....................... 19 Diskspace command....................... 20 Display during transfers................ 32 Double spacing.......................... 33 Erase command........................... 21 Extended function keys.................. 8 File command............................ 22 File name............................... 9 Fkhelp command.......................... 6,22 Function key............................ 17 Function key 1.......................... 5, 9 Function key 6.......................... 12,19 Function key 9.......................... 9,13,22,25,27 Function Keys........................... 6, 6 Limitations............................. 3 Line command............................ 15,23 Log command............................. 10 Modem................................... 5 Modem command........................... 24 Modify OTERM............................ 9 New disk................................ 9 New features/corrections................ 4 OTERM Commands.......................... 9 Printer................................. 3 Problems with nonprotocol file sending.. 34 Protocol file transfers................. 30,33 Quit command............................ 26 Receive command......................... 25 Receiving from an rcpm.................. 31 Revision level.......................... 3 RS232 interface......................... 5 Scrolling function keys................. 12,19,28 Send command............................ 27 Sending a file.......................... 17 Sending to an rcpm...................... 31 Transferring files with CompuServe...... 31 Transfers from OTERM to OTERM........... 30 Transfers with other systems............ 30 Type command............................ 28 Unable to establish communications...... 34 OTERM.DOC -- OTERM Terminal Simulator page 40 Using OTERM (summary)................... 5 Using the log........................... 11 Wait command............................ 29