
6
Agere Systems Inc.
Advisory
May 2001
for Version 1 and 1A of the Device
TDAT042G5 Device Advisory
Path Terminator (PT)
(continued)
PT3. Remote Defect Indicator (RDI) Behavior
The SONET standards require that when an RDI changes value, it should hold the value for a minimum of
20 frames. This applies to a
no error
state, which should be maintained for at least 20 consecutive frames.
However, it is also intended by the SONET standard that the occurrence of an
error
state should be reported
immediately.
TDAT042G5 responds to error conditions within 100 ms (
ANSI
*
T1.105 which states only that RDI-L must be gen-
erated or removed within 100 ms of detecting or terminating an incoming defect), in which case the two require-
ments become functionally the same.
Single-bit and enhanced RDI behave differently under the following conditions:
I
Transition from
error
state to
no error
state.
I
While in the
error
state, a subsequent error occurs.
The single-bit error RDI does not hold the no error state for 20 frames. However, the enhanced RDI does hold the
no error state for 20 consecutive frames.
Workaround
No workaround is available for this condition.
Corrective Action
The enhanced RDI indicator in future versions of the device will behave the same as the single-bit error indicator.
PT4. SS Pointer Interpretation Algorithm
The SDH standards do not require that the SS bits are set to binary 10 for SDH equipment. The SS bit values are
not used in determining a valid pointer value. Because of this, the SS pointer interpretation algorithm is not imple-
mented in the device. Bit 5 (RSSPTRNORM[A—D]) of PT control registers 0x0AA6, 0xAAE, 0x0AB6, and 0x0ABE
is not used. Bits 1 and 0 (RSSEXP[1:0]) of PT provisioning register 0x0AC7 are not used.
Workaround
No workaround is available for this condition.
Corrective Action
These bits will be removed from the PT registers in future revisions of the advance data sheet.
*
ANSI
is a registered trademark of American National Standards Institute, Inc.