Connecting Pstn, Isdn, Or Leased Circuit - CCTV DN-1808S Manual For Installer And User

1.4 Connecting PSTN, ISDN, or leased circuit

RS-232 (25PIN)
A/C ADAPTER
ISDN
LINE
A/C ADAPTER
CONNECTION TO COM 2
(9 PIN)
A/C ADAPTER
RS-232 (25PIN)
D.S.U.
LEASED
CIRCUIT
COM 2
D.S.U.
A/C ADAPTER
PSTN
9