The SyncTERM "dialing directory" is stored in a pair of plain-text list files (in .ini format), both named syncterm.lst:
A directory entry in the System List will be automatically copied to the User List when an entry is modified or "dialed".
When downloading a shared syncterm.lst file (e.g. from a web-site), it is recommended that you place that file in the System List location so as to not overwrite your User List.
On Windows, the User List is stored in
%APPDATA%\SyncTERM\
(example: C:\Users\YourName\AppData\Roaming\SyncTERM\)
while the System List is stored in
%ALLUSERSPROFILE%\SyncTERM\
(example: C:\ProgramData\SyncTERM\)
On Unix-like OSes (e.g. FreeBSD, Linux), the User List is stored in
~/.syncterm/
(example: /home/YourName/.syncterm/)
while the System List is stored in
/usr/local/etc/
On macOS, the User List is stored in
~/Library/Preferences/SyncTERM/
(example: /Users/YourName/Preferences/SyncTERM/)
while the System List is stored in
/Library/Preferences/SyncTERM/