
XRT84L38
352
OCTAL T1/E1/J1 FRAMER
REV. 1.0.1
11.0 E1 TRANSMIT FRAMER BLOCK
11.1
How to Configure XRT84L38 to Operate in E1 Mode
The XRT84L38 Octal T1/E1/J1 Framer supports DS1, J1 or E1 framing modes. Since J1 standard is very
similar to DS1 standard with a few minor changes, the J1 framing mode is included as a sub-set of the DS1
framing mode. All eight framers within the XRT84L38 silicon can be individually configured to support DS1, J1
or E1 framing modes.
N
OTE
:
If transmitting section of one framer is configured to support either one of the framing modes, the receiving section
is automatically configured to support the same framing modes.
The T1/E1 Select bit of the Clock Select Register (CSR) controls which framing mode, that is, T1/J1 or E1,
supported by the framer. The table below illustrates configurations of the T1/E1 Select bit of the Clock Select
Register (CSR).
CLOCK SELECT REGISTER (CSR) (INDIRECT ADDRESS = 0XN0H, 0X00H)
The purpose of the E1 Transmit Framer block is to embed and encode user payload data into frames and to
route this E1 frame data to the Transmit E1 LIU Interface block. Please note that the XRT84L38 has eight (8)
individual E1 Transmit Framer blocks. Hence, the following description applies to all eight of these individual
Transmit E1 Framer blocks.
The purpose of the E1 Transmit Framer block is:
To encode user data, inputted from the Terminal Equipment into a standard framing format.
To provide individual data control and signaling conditioning of each DS0 channel.
To support the transmission of HDLC messages, from the local transmitting terminal, to the remote receiving
terminal.
To transmit indications that the local receive framer has received error frames from the remote terminal.
To transmit alarm condition indicators to the remote terminal.
The following sections discuss the functionalities of E1 Transmit Framer block in detail. We will also describe
how to configure the XRT84L38 to transmit E1 frames according to system requirement of users.
11.2
How to Configure the Framer to Transmit and Receive Data in E1 Framing Format
The XRT84L38 Octal T1/E1/J1 Framer is designed to meet the requirement of ITU-T Recommendation G.704.
The E1 framer supports the following:
Frame Alignment Signal (FAS)
CRC-4 Multi-frame
The ITU-T Recommendation G.704 also specifies two forms of signaling that can be supported by the E1
Transport medium:
Channel Associated Signaling (CAS)
Common Channel Signaling (CCS)
The XRT84L38 framer supports both CAS, CCS signaling format together with Clear Channel without
signaling.
11.2.1
How to configure the framer to choose FAS searching algorithm
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UMBER
B
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AME
B
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T
YPE
B
IT
D
ESCRIPTION
6
T1/E1 Select
R/W
0 - The XRT84L38 framer is running in E1 mode.
1 - The XRT84L38 framer is running in T1 mode.