Vaisala HMM100 - Manual (Page 31)

Chapter 4 _________________________________________________________________ Operation
VAISALA ________________________________________________________________________ 29
will show you an error message instead. If this happens, restart
PuTTY and check the settings.
6. You may need to adjust the Local echo setting in the Terminal
category to see what you are typing on the serial line. To access the
configuration screen while a session is running, click the right
mouse button over the session window, and select Change
Settings... from the pop-up menu.
0807-004
Figure 15 PuTTY Terminal Application