2
As an enhancement to the
conventional SFP interface
defined in SFF-8074i, the AFBR-
57M5APZ is compliant to SFF-
8472 (digital diagnostic interface
for optical transceivers). Using
the 2-wire serial interface
defined in the SFF-8472 MSA,
the AFBR-57M5APZ provides
real time temperature, supply
voltage, laser bias current, laser
average output power and
received input power. This
information is in addition to
conventional SFP base data. The
digital diagnostic interface also
adds the ability to disable the
transmitter (TX_DISABLE),
monitor for Transmitter Faults
(TX_FAULT), and monitor for
Receiver Loss of Signal (RX_LOS).
Installation
The AFBR-57M5APZ can be
installed in any SFF-8074i
compliant Small Form Pluggable
(SFP) port regardless of host
equipment operating status. The
AFBR-57M5APZ is hot-
pluggable, allowing the module
to be installed while the host
system is operating and on-line.
Upon insertion, the transceiver
housing makes initial contact
with the host board SFP cage,
mitigating potential damage due
to Electro-Static Discharge (ESD).
Digital Diagnostic Interface
and Serial Identification
The 2-wire serial interface is
based on ATMEL AT24C01A
series EEPROM protocol and
signaling detail. Conventional
EEPROM memory, bytes 0-255 at
memory address 0xA0, is
organized in compliance with
SFF-8074i. New digital diag-
nostic information, bytes 0-255
at memory address 0xA2, is
compliant to SFF-8472. The new
diagnostic information provides
the opportunity for Predictive
Failure Identification, Com-
pliance Prediction, Fault
Isolation and Component
Monitoring.
Predictive Failure Identification
The AFBR-57M5APZ predictive
failure feature allows a host to
identify potential link problems
before system performance is
impacted. Prior identification of
link problems enables a host to
service an application via “fail
over” to a redundant link or
replace a suspect device,
maintaining system uptime in
the process. For applications
where ultra-high system uptime
is required, a digital SFP
provides a means to monitor two
real-time laser metrics asso-
ciated with observing laser
degradation and predicting
failure: average laser bias
current (Tx_Bias) and average
laser optical power (Tx_Power).
Compliance Prediction
Compliance prediction is the
ability to determine if an optical
transceiver is operating within
its operating and environmental
requirements. AFBR-57M5APZ
devices provide real-time access
to transceiver internal supply
voltage and temperature,
allowing a host to identify
potential component compliance
issues. Received optical power is
also available to assess
compliance of a cable plant and
remote transmitter. When
operating out of requirements,
the link cannot guarantee error
free transmission.
Fault Isolation
The fault isolation feature allows
a host to quickly pinpoint the
location of a link failure,
minimizing downtime. For
optical links, the ability to
identify a fault at a local device,
remote device or cable plant is
crucial to speeding service of an
installation. AFBR-57M5APZ
real-time monitors of Tx_Bias,
Tx_Power, Vcc, Temperature
and Rx_Power can be used to
assess local transceiver current
operating conditions. In
addition, status flags Tx_Disable
and Rx Loss of Signal (LOS) are
mirrored in memory and
available via the two-wire serial
interface.
Component Monitoring
Component evaluation is a more
casual use of the AFBR-
57M5APZ real-time monitors of
Tx_Bias, Tx_Power, Vcc,
Temperature and Rx_Power.
Potential uses are as debugging
aids for system installation and
design, and transceiver
parametric evaluation for
factory or field qualification. For
example, temperature per
module can be observed in high
density applications to facilitate
thermal evaluation of blades,
PCI cards and systems.
Description, continued