Karel MS48 Installation & Maintenance Guide
Edition 3.2
23
Figure A-18
EVM48 is an add-on card that is to be located on the MB48 motherboard.
The dimensions of EVM48 are 9 cm x 18 cm and the weight is 0.1 kg.
The dimensions of EVM-FE and EVM-DE are 6.5 cm x 3.5 cm.
II.10.
ISDN ADAPTOR – IA12, EXP-IA12
The IA12 ISDN Adaptor is an ETSI compatible terminal adaptor that serves as an
interface between the ISDN BRA-S0 lines coming through the network terminator
(NT1) of PTT and the analog lines of the MS48 system. The adaptor also supports
many EURO-ISDN facilities for Basic Rate Access.
The function of IA12 ISDN Adaptor is to support the ISDN BRA protocol of the
network in order to make bi-directional conversions between the ISDN BRA lines of
PTT and the analog lines of the MS48 system.
At basic capacity, IA12 ISDN Adaptor is capable of handling one S0 line coming
from NT1 of the PTT. This capacity can be further increased by means of an EXP-
IA12 Expansion Board which can also support one S0 line. Since each S0 line
offers two separate channels, the IA12 alone can convert two analog lines of the
MS48 system to one ISDN BRA-S0 line whereas the IA12 with EXP-IA12 can
convert four analog lines to two ISDN BRA-S0 lines.
The IA12 ISDN Adaptor communicates with the MS48 system through the data line
of KAREL telephones. Due to the current limitation on this data line which also
feeds the adaptor, it is not possible to connect more than three adaptors to the
same system, and the third adaptor cannot have the EXP-IA12 Expansion Board.
As a result, the available ISDN line capacities of MS48 system are illustrated as
follows:
Summary of Contents for MS48
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