--- name: "modemu" section: "1" platform: "linux" package: "modemu" version: "0.0.1-10" release: "Debian 6.0 (Squeeze)" platforms: ["linux"] url: "https://new.carta.tech/modemu" --- # modemu(1) dialup TCP connecting ## NAME modemu - dialup TCP connecting ## SYNOPSIS **modemu** \[**-c** *comm\_prog*\] \[**-d** *pty\_master*\] \[**-e** *atcmds*\] \[**-h**\] \[**-s**\] \[**-**\] ## DESCRIPTION **Modemu** is a TELNET client with a modem-like user interface. It can redirect its I/O via a [**pty**(4)](/pty/4.md) so that a comm program can handle the pty as a tty with a real modem. **Modemu** has two major modes: a command mode and online mode. When invoked, **modemu** is in the command mode, waiting for AT commands input. Entering a D or O command will put into the online mode, in which **modemu** communicate with a remote host. Connection closing or a escape command input returns to the command mode. ## OPTIONS - **-c** *comm\_prog* Invoke a comm program *comm\_prog*. **Modemu** invokes it by passing /bin/sh an option \`-c *comm\_prog*'. Therefore, any [**sh**(1)](/sh/1.md) commands can be specified. The string *comm\_prog* can include a \`%s', which will be replaced with the device name of the slave device after removal of the initial "/dev/". Example: modemu -c "xc -l %s" - **-d** *pty\_master* Open a file *pty\_master* and talk through it. A named pipe can be a *pty\_master* as well as a pty master device because **modemu** doesn't ioctl a *pty\_master*. - **-e** *atcmds* Execute a series of AT commands *atcmds* initially. *Atcmds* must have an \`AT' or \`at' prefix. D and O commands in *atcmds* are ignored. - **-h** Print a usage summary. - **-s** Print the last two letters of a device name. The device is a pty master device which **modemu** talks through. Therefore, when **modemu** prints \`p8', comm program must open /dev/tty*p8*. - **\`-'** **Modemu** talks through the standard input/output. (Default) Note: -c, -d, -s and - options are exclusive each other. If two or more of the options are specified, only the last one is effective. ## COMMAND MODE Command mode expects lines in the following format: - \[*garbage*\]*at*\[*sp*\]\[*cmd*\[*sp*\]\]...*cr* where *at* is an \`AT' or \`at', *sp* is spaces, *cr* is a carriage return character (register S3), *garbage* is a string includes no *at*. If a \`#' prefixes a line, the line is ignored. Available *cmd*s are listed below. They are all case in-sensitive except for some literally used arguments. A (\*) marks default settings. - **D***str* Dialing command. Open a connection to *host*. If *port* is specified, **modemu** attempts to connect with the port instead of the default TELNET port, and doesn't initiate TELNET option negotiation. The following formats are available for *str*: - *host*\[:*port*\] *Host* is an Internet address in numbers-and-dots notation. Optional *port* is a port number. - "*host*\[:*port*\]\["\] *Host* is an Internet address or host name. Optional *port* is a port number or service name. The closing double quote can be omitted if no command follows. *Str* can be prefixed with \`T', \`P', \`*digit*W' and/or \`*digit*,'. The prefixes are simply ignored.\ Example: ATDT0W127.0.0.1\ ATDP"foo.bar.jp:daytime - **E1** No operation. - **F1** No operation. - **H**\[**0**\] Close the current TELNET session. - **I***n* Print various information. - I4 Current settings - I5 \`&W'ed settings - I6 TELNET option states - I7 **Modemu** version - **O**\[**0**\] Return to online mode. - **P** No operation. - **Q**\[**0**\] No operation. - **T** No operation. - **V1** No operation. - **X**\[**0**\] No operation. - **S***n***=***m* Set S-register S*n* to *m*. A number from 0-255 is allowed for *m*. - **S***n***?** Print an S-register S*n*'s value. - **Z** Close the current TELNET session, and restore \`&W'ed settings. - **&W** Save current settings. The saved settings will be lost with the end of the process because they are not stored into NV-RAM nor files. - **%B***n***=***m* Control TELNET binary option. Valid values for *n* are: - 0 Control the local (modemu) option - 1 Control the remote (TELNET server) option Valid values for *m* are: - 0 Request non-binary transmission mode (\*) - 1 Request binary transmission (8bit through) mode - *above+2* Disconnect if the request is refused Example: - AT%B1=1 Requesting binary mode in remote-to-modemu direction - AT%B0=3%B1=3 Requesting binary mode in both remote-to-modemu and modemu-to-remote direction. No use connecting in non-binary mode (using file xfer protocol or something) - **%D***n* Control dial-canceling. - %D0 A keypress cancels dialing (\*) - %D1 Keypresses don't cancel dialing - **%L***n* Control line-mode. - %L0 Request character-at-a-time mode (\*) - %L1 Request line-at-a-time mode (old line-mode). Input characters are buffered and not sent until a CR character is entered. - **%Q** Quit **modemu**. - **%R***n* Control raw-mode. - %R0 Normal mode (\*) - %R1 Raw mode. **Modemu** transmits every octet as received. Applied to both remote-to-modemu and modemu-to-remote direction. Override %B and %L settings. - **%T***str* Control TELNET terminal-type option. - %T0 Refuse terminal-type option - %T1 Same as %T="$**TERM**" (**TERM** environment value is used) (\*) - %T="*term*\["\] Send *term* as the terminal-type if remote requests. The closing double quote can be omitted if no command follows. - **%V***n* Control verbose level. %V0 (\*) is the quietest, and adding following values to *n* lets **modemu** print more information to stderr. - \+1 Print misc info to make up for less descriptive ATX0 indication - \+2 Print TELNET option negotioation ## ONLINE MODE **Modemu** recognizes only the following command when in online mode. - *wait* **+++** *wait* Escape to command mode. The \`+++' must be input within the guard time. *Wait* is a period of time longer than the guard time without hitting any key. See also S2 and S12 register descriptions. ## S REGISTERS Only meaningful registers are listed here. Values in braces are default ones. - **S2** Escape character code. (43 = \`+') - **S3** Carriage return character code. (13) - **S4** Line feed character code. (10) - **S5** Backspace character code. (8) - **S7** Connecting attempt time limit in seconds. (20) - **S12** Escape sequence guard time in 50ths of a second. (50) ## ENVIRONMENT VARIABLES - **MODEMU** Initially evaluated as AT commands (before -e option argument is evaluated). Must have an \`AT' or \`at' prefix. - **TERM** See %T1 command description. ## AUTHOR Toru Egashira (egashira@nwk.CL.nec.co.jp) ## SEE ALSO [telnet(1)](/telnet/1.md), *Your favorite modem's manual* ## BUGS No dial-resriction, or blacklisting, capability. So using **modemu** maybe unlawful in some countries. B)