XRT86L30
SINGLE T1/E1/J1 FRAMER/LIU COMBO
REV. 1.0.1
11.2
Transmit/Receive High-Speed Back-Plane Interface
The High-speed Back-plane Interface supports payload data to be taken from or presented to the Terminal
Equipment at different data rates. In the non-multiplexed mode, payload data of each channel are interfaced to
the Terminal Equipment separately. Each channel uses its own serial clock, serial data, single-frame
synchronization signal and multi-frame synchronization signals.
11.2.1
T1 Transmit/Receive Interface - MVIP 2.048 MHz
The Back-plane interface is processing data at an E1 equivalent data rate of 2.048Mbit/s. The local Terminal
Equipment should pump in data grouped in 256-bit frame 8000 times every second. Each frame consists of
thirty-two octets as in E1. The local Terminal Equipment maps a 193-bit T1 frame into this 256-bit format as
described below:
1. The Framing (F-bit) is mapped into MSB of the first E1 Time-slot. The local Terminal Equipment will stuff
the other seven bits of the first octet with don't care bits that would be ignored by the framer.
2. Payload data of T1 Time-slot 0, 1 and 2 are mapped into E1 Time-slot 1, 2 and 3.
3. The local Terminal Equipment will stuff E1 Time-slot 4 with eight don't care bits that would be ignored by
the framer.
4. Following the same rules of Step 2 and 3, the local Terminal Equipment maps every three time-slots of T1
payload data into four E1 time-slots.
The mapping of T1 frame into E1 framing format is shown in the table below.
TABLE 174: THE MAPPING OF T1 FRAME INTO E1 FRAMING FORMAT
T1
E1
T1
E1
T1
E1
T1
E1
F-Bit
TS0
TS0
TS1
TS1
TS2
TS2
TS3
Don't Care Bits
TS4
TS3
TS5
TS4
TS6
TS5
TS7
Don't Care Bits
TS8
TS6
TS7
TS8
Don't Care Bits
TS12
TS9
TS10
TS14
TS16
TS22
TS22
TS30
TS11
TS15
TS17
TS23
TS23
TS31
TS9
TS10
TS13
TS18
TS19
TS26
TS11
TS14
TS19
TS20
TS27
TS13
TS15
TS21
TS21
TS29
Don't Care Bits
TS16
TS12
TS17
TS18
TS25
Don't Care Bits
TS20
Don't Care Bits
TS24
Don't Care Bits
TS28
211
EXAR [ EXAR CORPORATION ]
