PEB2080 SIEMENS [Siemens Semiconductor Group], PEB2080 Datasheet - Page 36

• Manufacturer Part Number: PEB2080
• Description: S/T Bus Interface Circuit(SBC)
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Functional Description
Use of ECHO
Local communication of terminals connected to an S bus may be implemented by using the auxiliary
ECHO output (pin X2, in TE mode only). The timing of ECHO is identical to that of output SDO:
however, the signal is “1” everywhere except in bit positions 24 and 25 of the IOM frame, where it
is equal to the echo bits received from the S interface. Thus a layer-2 device (e.g. the ISDN
Communication Controller PEB 2070) connected to ECHO is able to receive or “hear” all other
terminals. As a special application, an S-bus local area network may be built using several TE
SBC’s and one NT (or an NT star configuration). Communication in the D and E channel is half
duplex.
Figure 19
Star Configuration in NT
Semiconductor Group
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