Ncu Pba - Toshiba DP120F Service Manual

4. NCU PBA

This section describes the function of each circuit on the NCU PBA.
The NCU PBA consists of the transformer, relay, analog switch, and other peripheral devices.
It controls switching of the line path, generates dial pulses, detects line current, detects a ring
signal, and monitors the line.
The NCU PBA is connected to CN3 on the Main PBA. It can also be connected optionally to
CN4.
The description of this section is based on the NCU PBA for Line 1.
US/CA/TW models
07-04-00
Fig. 7-4-1
March 2000 © TOSHIBA TEC 7-77 DP120F/DP125F Circuit Description