DS21455 Maxim Integrated Products, DS21455 Datasheet - Page 116

• Manufacturer Part Number: DS21455
• Description: Network Controller & Processor ICs Quad E1-T1-J1 Single -Chip Transceiver (S
• Manufacturer: Maxim Integrated Products

Specifications of DS21455

• Product: Framer
• Number Of Transceivers: 4
• Data Rate: 64 Kbps
• Supply Voltage (max): 3.465 V
• Supply Voltage (min): 3.135 V
• Supply Current (max): 328 mA
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Mounting Style: SMD/SMT
• Package / Case: BGA

DS21455/DS21458 Quad T1/E1/J1 Transceivers
20. ELASTIC STORES OPERATION
The DS21455/DS21458 contain dual two-frame, fully independent elastic stores, one for the receive
direction and one for the transmit direction. The transmit- and receive-side elastic stores can be
enabled/disabled independent of each other. Also, each elastic store can interface to either a 1.544MHz or
2.048MHz/4.096MHz/8.192MHz/16.384MHz backplane without regard to the backplane rate to which
the other elastic store is interfacing.
The elastic stores have two main purposes. First, they can be used for rate conversion. When the device is
in the T1 mode, the elastic stores can rate-convert the T1 data stream to a 2.048MHz backplane. In E1
mode, the elastic store can rate-convert the E1 data stream to a 1.544MHz backplane. Second, they can be
used to absorb the differences in frequency and phase between the T1 or E1 data stream and an
asynchronous (not locked) backplane clock (which can be 1.544MHz or 2.048MHz). In this mode, the
elastic stores will manage the rate difference and perform controlled slips, deleting or repeating frames of
data in order to manage the difference between the network and the backplane.
The elastic stores can also be used to multiplex T1 or E1 data streams into higher backplane rates. See the
Interleaved PCM Bus Operation section.
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