The S-Bus Interface Circuit (SBC) PEx 2080 implements the four-wire S/T-interface used to link voice/data terminals to an ISDN. Through selection of operating mode, the device may be employed in all types of applications involving an S interface. Two or more SBC´s can be used to build a point to-point, passive bus, extended passive bus or star configuration.
Specific ISDN applications of the SBC include: ISDN terminals, ISDN network termination (Central Office and PABX applications), and PABX trunk lines to Central Office.
The device provides all electrical and logical functions according to CCITT recommendation I.430. These include: mode-dependent receive timing recovery, D-channel access and priority control, and automatic handling of activation/deactivation procedures. The SBC does not require direct microprocessor control.
The SBC is an IOM compatible, 22-pin CMOS device. It operates from a single + 5 V supply and features a power-down state with very low power consumption.

FEATUREs
● Full duplex 2B + D S/T-interface transceiver according to CCITT I.430
● Conversion of the frame structure between the S/T and IOM® interfaces
● D-channel access control
● Activation and deactivation procedures according to CCITT I.430
● Built-in wake-up unit for activation from power-down state
● Adaptively switched receive thresholds
● Control via IOM interface
● Several operating modes
● Receive timing recovery according to selected operating mode
● Frame alignment with absorption of phase wander in trunk line applications
● Switching of test loops
● Advanced CMOS technology
● Low power consumption:
   PEB 2080: standby less than 5 mW
                            active max. 65 mW
   PEF 2080: standby less than 6.5 mW
                            active max. 70 mW