SPM - Comparison chart

Starting from version 4.0 Serial Port Monitor is divided into Serial Port Monitor Standard Edition and Serial Port Monitor Professional Edition. 

The difference you can see here: 

# Feature Standard Professional
1 Any serial port software/hardware can be analyzed
yes
yes
2 Monitor any number of serial ports at once
yes
yes
3 Supports all COM-port types
yes
yes
4 Intercepts all data read from/written to COM port
yes
yes
5 Built-in search
yes
yes
6 Various monitoring visualizers
yes
yes
7 Incoming and outgoing data streams logging
yes
yes
8 Tracing all serial input/output control codes
yes
yes
9 Copying all recorded data to clipboard
yes
yes
10 Customizable monitoring session logging
yes
yes
11 Saving, loading and exporting all monitored data
yes
yes
12 Full duplex mode
yes
yes
13 Unique stream filtering tools with presets
yes
yes
14 Emulates data sending for monitored application
yes
yes
15 Monitoring already opened serial port
no
yes
16 Advanced Send Dialog: send various types of data
no
yes