Справочник Пользователя для Netopia PN Series

The Netopia Router includes an internal termination switch for 
terminating the S/T bus. The S/T bus is the connection from the 
Router to the NT1 or wall jack on your ISDN line. The S/T bus must 
be properly terminated to avoid ISDN communications errors.

The Netopia Router ships with its internal termination switch set to 
the off position. This means that you should already have S/T bus 
termination. If you are unsure of whether you have S/T bus 
termination, contact your ISDN service provider.

If you do not have S/T bus termination, you should set the internal 
termination switch to the on position.

The switch is located just inside a rear-panel ventilation hole that is 
visibly larger than the other holes, as shown in the following 
illustration:

Use a pointed object, such as a pen, to carefully reach inside the 
correct ventilation hole and slide the switch to the left. This is the 
on position, with termination in effect.

Switch

Switch

in on
position

in off
position

Large vent hole