Answering machine on your Linux box
Or you could use a pre-recorded file. Record your message and save it as wav format. Make sure that the file is mono and not stereo. Now you need to run it through a few programs ( included in the vgetty distribution ) to get the final output in the rmd format.
wavtopvf filename.wav filename.pvf
Convert the wav to pvf format
pvfspeed -s 7200 filename.pvf filename2.pvf
Change the sampling rate of the pvf file to 7.2Khz. Each modem supports a particular sampling rate and our Rockwell based modem required this sampling rate. The command below will not work if the input pvf file is not in the correct sampling rate. Pvftormd will fail and also tell you what the desired sampling rate is for your modem.
pvftormd Rockwell 4 filename2.pvf filename.rmd
Pvttormd again needs to know what modem to create the rmd file for because the encoding is modem specific. Use pvfspeed -L to see the list of supported modem types. The modem type is case sensitive. The next parameter that can be seen here is 4, which is the number of bits per sample. Possible values for your modem will be shown in the list of supported modem types. More bits means larger rmd files but better sound quality.
The above series of commands can be compressed into a single command line as given below.
wavtopvf filename.wav | pvfspeed -s 7200 | pvftormd Rockwell 4 > filename.rmd
Copy the output rmd file to /var/spool/voice/messages as standard.rmd. Vgetty offers you the option of using multiple greeting files. Create any number of files and place them in the messages directory. Then create or edit the file named Index ( watch the case! ) and put the filenames of the greeting files here. Only one filename per line. Vgetty will now use any of the files specified in there as the greeting message.
That's the setup of vgetty. Now you should start it by giving the command init q. Vgetty will now be running and ready to receive your phone calls.
After picking up the phone vgetty will play the greeting message and then send a beep through the line. Then it switches to recording mode to save the incoming messages. These are saved in the incoming messages folder under /var/spool/voice/incoming.
The files can be played over the phone using the following command.
vm play filename
You can also play it over your sound card using the following command.
rmdtopvf filename.rmd | pvfspeed -s 8000 | pvftobasic > /dev/audio