EXP Computer ThinConnect4 - Manual (Page 145)

ThinConnect4 <135>
9.3.2 Leased Line
Basically, you can not disconnect a leased line, however, you can switch off the TA’s
power supply if you want to disconnect the Leased line.
To connect the leased line again, please refer to 9.2 Connection Types (Page 131)
End of 9.3 Disconnect the network