YTD428 Datasheet, PDF (5/14 Pages) YAMAHA CORPORATION – DSU LSI for the ISDN Terminal Equipment

s Configuration example of a device with a built-in DSU that uses a TTL interface at
the T ref. pt.
When using YTD428 with YAMAHA'S S/T reference point interface LSI to create a device with a built-in
DSU, they can be connected directly through the TTL interface. This results in a reduction of pulse
transformer parts.
RA / RB
TA / TB
T ref.
pt. I/F
YTD428
I/F
switch
CT
and
LT
U ref.
pt. I/F
DSU section
L1
L2
U ref. pt.
driver
TTL I/F
Call control
circuit
(No transformer is requied)
YTD418 or
YTD423
Layer 3 information
(Bch data)
s Example of using T reference point driver / receiver section independently
By setting the Interface switch, the drive / receiver of the T reference point interface section can be separated
from the circuit termination (CT) and line termination (LT) section and be used independently.
The user can enable or disable this feature as necessary.
RA / RB
TA / TB
T ref.
pt. I/F
YTD428
I/F
switch
CT
and
LT
U ref.
pt. I/F
DSU section
L1
L2
U ref. pt.
driver
TTL I/F
Call control
circuit
(No transformer is required)
YTD418 or
YTD423
Layer 3 information
(Bch data)
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