
XRT84L38
381
REV. 1.0.1
OCTAL T1/E1/J1 FRAMER
The Receive Signaling Substitution Control [1:0] bits can select all ones substitution, two-code signaling
substitution, four-code signaling substitution, or sixteen-code signaling.
The XRT84L38 framer can substitute received signaling bits with all ones. Two-code signaling substitution is
done by substituting all the four signaling bits with the content of the SIG2-A bit of the register. Four-code
signaling substitution is done by substituting the first two signaling bits of the four with the SIG4-A bit and the
last two signaling bits of the four with the SIG4-B bit of the RSSR register. Sixteen-code signaling substitution
is implemented by substituting the four signaling bits with the content of SIG16-A, SIG16-B, SIG16-C, and
SIG16-D bits of RSSR register respectively.
The table below shows configurations of the Receive Signaling Substitution Control [1:0] bits of the Receive
Signaling Control Register.
RECEIVE SIGNALING CONTROL REGISTER (RSCR) (INDIRECT ADDRESS = 0XN2H, 0X40H - 0X5FH)
12.5
How to Configure the Framer to Detect Alarms and Error Conditions
The XRT84L38 T1/J1/E1 Octal Framer can be configured to monitor quality of received E1 frames. It can
generate error indicators if the local receive framer has received error frames from the remote terminal. If
corresponding interrupt is enabled, the local microprocessor operation is interrupted by these error conditions.
Upon microprocessor interruption, the user can intervene by looking into the error conditions.
At the same time, the user can configure the XRT84L38 framer to receive alarms and error indications to
remote terminal. Different alarms and error indications will be received depending on the error condition.
The section below gives a brief discussion of the error conditions that can be detected by the XRT84L38
framer and error indications that will be generated.
12.5.1
How to configure the framer to detect AIS Alarm
2
SIG16-B
SIG4-B
SIG2-A
Sixteen-Code Signaling bit B
Four-Code Signaling bit B
Two-Code Signaling bit A
1
SIG16-C
SIG4-A
SIG2-A
Sixteen-Code Signaling bit C
Four-Code Signaling bit A
Two-Code Signaling bit A
0
SIG16-D
SIG4-B
SIG2-A
Sixteen-Code Signaling bit D
Four-Code Signaling bit B
Two-Code Signaling bit A
B
IT
N
UMBER
B
IT
N
AME
B
IT
T
YPE
B
IT
D
ESCRIPTION
3-2
Receive Signaling
Substitution Con-
trol
R/W
00 - The received signaling bits are replaced by all ones and send to the
external equipment.
01 - Two-code signaling substitution is applied to the received signaling
bits. The replaced signaling information is sent to the external equipment.
10 - Four-code signaling substitution is applied to the received signaling
bits. The replaced signaling information is sent to the external equipment.
11 - Sixteen-code signaling substitution is applied to the received signaling
bits. The replaced signaling information is sent to the external equipment.
RECEIVE SUBSTITUTION SIGNALING REGISTER (RSSR) (INDIRECT ADDRESS = 0XN02H, 0X80H -
0X9FH)
B
IT
N
UMBER
B
IT
N
AME
B
IT
T
YPE
B
IT
D
ESCRIPTION