![](http://datasheet.mmic.net.cn/330000/PM8315_datasheet_16444435/PM8315_131.png)
STANDARD PRODUCT
PM8315 TEMUX
DATASHEET
PMC-1981125
ISSUE 7
HIGH DENSITY T1/E1 FRAMER WITH
INTEGRATED VT/TU MAPPER AND M13 MUX
PROPRIETARY AND CONFIDENTIAL
116
and reduce mapping jitter to 1.0 UI. To reduce mapping jitter even further, a
dither technique is inserted between the control loop and the stuff bit generator
resulting in an acceptable desynchronizer mapping jitter of about 0.3 UI.
The Tributary Mapper may optionally act as a time switch. When Time Switch
Enable is active, the association of Tributary Mapper VT Payloads to logical FIFO
data streams is software configurable. There are two pages in the time switch
configuration RAM. One page is software selectable to be the active page and
the other the stand-by page. The configuration in the active page is used to
associate outgoing VT Payloads to logical FIFOs. The stand-by page can be
programmed to the next switch configuration. Change of page selection is
synchronized to incoming stream frame boundaries. When Time Switch Enable
is inactive, the association of outgoing VT Payloads to logical FIFOs is fixed.
The TTMP outputs the STS-1, TUG3 in a STM-1/VC4 or STM-1/VC3 with the bit
asynchronous mapped T1s or E1s onto an internal bus for further processing by
the Transmit Tributary Payload Processor block.
9.36 Serial In to Parallel Out Converter (SIPO)
The Serial In to Parallel Out Converter (SIPO) accepts serial data from up to 28
T1 or 21 E1 sources and converts these streams to byte serial format. The bytes
are passed to the Transmit Tributary Mapper (TTMP) for bit asynchronous
mapping into the STS-1.
9.37 DS3 Mapper ADD Side (D3MA)
The DS3 Mapper ADD Side (D3MA) block maps a DS3 signal into an STS-1
(STM-0/AU3) payload and compensate for any frequency differences between
the incoming DS3 serial bit rate (TICLK) and the available STS-1 (STM-0/AU3)
SPE mapped payload capacity. The asynchronous DS3 mapping consists of 9
rows every 125 μs (8 KHz). Each row contains 621 information bits, 5 stuff
control bits, 1 stuff opportunity bit, and 2 overhead communication channel bits.
Fixed stuff bytes are used to fill the remaining bytes. Please refer to section 9.32
for a description of the DS3 mapping.
9.37.1 DS3 Mapper Serializer
High speed serial data from the DS3-TRAN block is deserialized and written into
the Elastic Store.