YTD428 YAMAHA [YAMAHA CORPORATION], YTD428 Datasheet - Page 5

• Manufacturer Part Number: YTD428
• Description: DSU LSI for the ISDN Terminal Equipment
• Manufacturer: YAMAHA [YAMAHA CORPORATION]

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.
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.
Configuration example of a device with a built-in DSU that uses a TTL interface at
Example of using T reference point driver / receiver section independently
the T ref. pt.
RA / RB
TA / TB
RA / RB
TA / TB
pt. I/F
T ref.
pt. I/F
T ref.
TTL I/F
YTD418 or
Layer 3 information
TTL I/F
YTD423
YTD418 or
Layer 3 information
(Bch data)
YTD423
switch
(Bch data)
I/F
switch
YTD428
I/F
YTD428
(No transformer is requied)
(No transformer is required)
Call control
and
CT
LT
circuit
Call control
and
CT
LT
circuit
U ref. pt.
driver
U ref. pt.
driver
pt. I/F
U ref.
pt. I/F
U ref.
DSU section
DSU section
L1
L2
L1
L2
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