This question should be in physics so this is my answer in C&T format-go to a online shop and order one or the pieces then follow the instructions that will be given.
The fax modem is used to send and receive fax messages by only having phone line (fax machine is not required). The scanned documents should be saved as digital file (image or PDF format) in order to be sent. So, in order to send a portion of a map you should first convert the map into digital file and than simply send it through the fax modem. The best way to convert it to a digital file is to use an optical character recognition (OCR).
In general, synchronous communication means you have to wait for the answer all the time. The programming logic is simpler, but the cost that you spend a lot of time waiting.
If the options are:
<span>a. The people communicating don't need to be online at the same time.
b. There is lag time in the communication.
c. The communication occurs in real time.
a is false, you do need to be online to receive the message
b is true, typically you continue only after an acknowledgement
c is true, you wait for acknowledgement that occurs in real time (not necessarily fast though)</span>
