PEB2080 SIEMENS [Siemens Semiconductor Group], PEB2080 Datasheet - Page 20

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

Functional Description
Digital Interface
IOM Frame Structure
The SBC is provided with a digital interface, the IOM interface, for communication with other ISDN
devices, in other words with units realizing OSI layer-1 functions (such as the ISDN Echo
Cancellation Circuit IEC PEB 2090) or layer-2 functions (such as the ISDN Communication
Controller ICC PEB 2070).
The IOM interface is a four-wire serial interface with: a bit clock, a frame clock and one data line per
direction (figure 7).
The ISDN data rate of 144 kbit/s (B1 + B2 + D) is transmitted transparently in both directions over
the interface. In addition, it is necessary to interchange control information for activation and
deactivation of OSI layer 1 and for switching of test loops. This information is transferred using time
division multiplexing with a 125- s total frame length.
Figure 7
IOM
®
Interface Signals
Semiconductor Group
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