psf21911 ETC-unknow, psf21911 Datasheet - Page 8

• Manufacturer Part Number: psf21911
• Description: Isdn Echocancellation Circuit Terminal Applications Iec-q
• Manufacturer: ETC-unknow

1
The PSB 21911, IEC-Q TE Version 5.2, is a specific derivative of the PEB 2091, IEC-Q
for terminal and small PBX applications. It features all necessary functions required for
NTs and terminal applications like PC add-on cards and terminal adapters.
In stand-alone mode the PSB 21911 IEC-Q TE Version 5.2 can be used fully pin
compatible to IEC-Q V4.4 and former versions. In µP mode it offers a parallel or serial
microprocessor interface.
The Processor Interface (PI) of the IEC-Q TE V 5.2 establishes the access of a
microprocessor between U-interface and IOM-2. It’s main function is illustrated in
figure 1.
Figure 1
In µP mode B channels, D channel, C/I codes and Monitor commands can either be
passed between the U-transceiver and IOM-2 directly, or they can be looped through the
µP via the PI. Any selection of "passed" or "looped" channels can be programmed via a
control register.
The µP-interface mode is enabled by setting the pin PMODE to "1". This pin was not to
be connected in older versions of the IEC-Q. Its internal pull down resistor selects the
stand-alone mode, if the pin is left open.
In stand-alone mode the IEC-Q TE is controlled exclusively via the IOM-2 interface and
mode selection pins.
Semiconductor Group
Overview
Stand-Alone Mode (left) and µP Mode (right)
IOM -2
R
U
8
IOM -2
R
FSC
PI
ITS10193
U
PSB 21911
PSF 21911
Overview
11.97