Functional Description
2.3.5
B-Channel Switching
The ISAC-S contains two serial interfaces, SLD and SSI, which can serve as interfaces to B
channel sources/destinations. Both channels B1 and B2 can be switched independently of one
another to the IOM interface and to the four-wire S/T interface (figure 20).
The following possibilities are provided:
– Switching from/to SSI
– Switching from/to SLD
– IOM looping
– SLD looping.
The microcontroller can select the B-channel switching in the SPCR register. In figure 21 all
possible selections of the B-channel routes and access to B-channel data via the
microprocessor interface are illustrated. This access from the microcontroller is possible by
writing or reading the C1R/C2R register or reading the B1CR/B2CR register (see
Synchronous Transfer, paragraph 2.3.6).
SSI
ISDN
Basic
Access
SSI
R
ISDN
Basic
Access
B-Channel
Sources /
Destinations
IOM
Interface
Layer 1
SLD
Functions
S/T
SLD
Registers : C1R / C2R
B1CR / B2CR
SPCR
µ
P-Interface
ITB00862
Figure 20
Principle of B-Channel Switching
Semiconductor Group
47
INFINEON [ Infineon ]
