XRT72L50 Datasheet, PDF (108/471 Pages) Exar Corporation – SINGLE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

XRT72L50
SINGLE CHANNEL DS3/E3 FRAMER WITH HDLC CONTROLLER
REV. 1.2.1
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will read in the contents of this register, and insert it into the TR byte-field, within the very next outbound E3
frame.
This particular byte-field should contain the pattern "[1, C6, C5, C4, C3, C2, C1, C0]" where the bits C6 through
C0 are the results of a CRC-7 calculation over the previous 16-byte frame.
NOTE: The XRT72L50 Framer IC will not compute this CRC-7 value. It is up to the user's hardware and/or software to
compute this value, prior to writing it into this register.
2.3.6.8 Transmit E3 TTB-1 Register (E3, ITU-T G.832)
TxE3 TTB-1 Register (Address = 0x39)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
TxTTB-1[7:0]
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
0
0
0
This Read/Write byte-field, along with the TxTTB-0 and TxTTB-2 through TxTTB-15 register permit a user to
define a Trail Access Point Identifier sequence of bytes, that will be transmitted to the Remote Terminal. The
Remote Receiving Terminal will use this sequence of bytes to verify that it is connected to the proper
Transmitting Terminal. The Transmit DS3/E3 Framer block will take the contents of these 16 registers, and
insert them into the TR byte of the outbound E3 frame. In the second of a set of 16 E3 Frames, the Transmit
DS3/E3 Framer block will read in the contents of this register, and insert it into the TR byte-field, within the very
next outbound E3 frame.
The contents of this register, along with Tx TTB-2 through Tx TTB-15 are used to transmit 15 ASCII characters
required for the E.164 numbering format.
2.3.6.9 Transmit E3 TTB-2 Register (E3, ITU-T G.832)
TxE3 TTB-2 Register (Address = 0x3A)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
TxTTB-2[7:0]
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
0
0
0
This Read/Write byte-field, along with the TxTTB-0, TxTTB-1 and TxTTB-3 through TxTTB-15 register permit a
user to define a Trail Access Point Identifier sequence of bytes, that will be transmitted to the Remote Terminal.
The Remote Receiving Terminal will use this sequence of bytes to verify that it is connected to the proper
Transmitting Terminal. The Transmit DS3/E3 Framer block will take the contents of these 16 registers, and
insert them into the TR byte of the outbound E3 frame. In the third of a set of 16 E3 Frames, the Transmit DS3/
E3 Framer block will read in the contents of this register, and insert it into the TR byte-field, within the very next
outbound E3 frame.
The contents of this register, along with Tx TTB-1, and Tx TTB-3 through Tx TTB-15 are used to transmit 15
ASCII characters required for the E.164 numbering format.
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