Creating Messages ------------------------------------------------------------------------- To input characters, you must go inside the project. In the block section of the code side panel, all available ASCII characters are made as blocks. Drag and drop them in order under the character input section. This section is not marked or labeled, but it can be found easily. Look for the example message, then in place of that, put your message. Remember to put the 'Finish' block at the end of your message so the code knows when to stop. Press the 'Start' button, located in the GUI, to play your message into FSK. Reset Counter ------------------------------------------------------------------------- If the message finishes playing, but the counters have not reset, press the 'Reset Counter' button located in the GUI, to reset the counters. This can also be used to reset the counter while the message is playing. Settings ------------------------------------------------------------------------- To access the settings, press the 'Settings' button located in the GUI. In the settings menu, you can change variables such as the baud rate. Press the X button in the menu to close it.
About ------------------------------------------------------------------------- This program is meant to simulate the sound of an old dial up modem from the late 70's to early 80's, specifically modems using the Bell 101, Bell 103, and V.21 communication standards. Back in those days, modems where primarily used for sending 8-bit ASCII text for builtin board systems and online services. The speeds available in this simulation are not common speeds and this simulation does not follow any dial up modem communication standards. Basically this won't work if you send it down a phone line to another modem. Your Own Use ------------------------------------------------------------------------- However, you are welcome to create your own digital communication standard using this program for you and your friends. This could be used, for example, over the phone line or over HAM radio, as long as the other end can decode it. How FSK Works ------------------------------------------------------------------------- The idea of a dial up modem is to turn digital data into audio to be sent over the phone line. One way of doing this is to use frequency shift key. This means that the frequency is shifted for different values. For modems (using Bell 101, Bell 103, and V.21) there are four frequencies used. The originating modem would play a 1270 Hz tone for a one and a 1070 Hz tone for a zero. The answering modem would play a 2225 Hz tone for a one and a 2025 Hz tone for a zero. This simulation uses the same tones as the answering modem would. Created September 10th, 2020
