<s>
Small	B-Protocol
Form-factor	I-Protocol
Pluggable	I-Protocol
(	O
SFP	O
)	O
is	O
a	O
compact	O
,	O
hot-pluggable	B-Device
network	O
interface	O
module	O
format	O
used	O
for	O
both	O
telecommunication	O
and	O
data	O
communications	O
applications	O
.	O
</s>
<s>
An	O
SFP	B-Protocol
interface	I-Protocol
on	O
networking	B-Device
hardware	I-Device
is	O
a	O
modular	O
slot	O
for	O
a	O
media-specific	O
transceiver	O
,	O
such	O
as	O
for	O
a	O
fiber-optic	B-Architecture
cable	I-Architecture
or	O
a	O
copper	O
cable	O
.	O
</s>
<s>
modular	B-Architecture
connectors	I-Architecture
in	O
Ethernet	B-Protocol
switches	I-Protocol
)	O
is	O
that	O
individual	O
ports	O
can	O
be	O
equipped	O
with	O
different	O
types	O
of	O
transceivers	O
as	O
required	O
.	O
</s>
<s>
The	O
SFP	O
replaced	O
the	O
larger	O
gigabit	B-Protocol
interface	I-Protocol
converter	I-Protocol
(	O
GBIC	B-Protocol
)	O
in	O
most	O
applications	O
,	O
and	O
has	O
been	O
referred	O
to	O
as	O
a	O
Mini-GBIC	B-Protocol
by	O
some	O
vendors	O
.	O
</s>
<s>
SFP	B-Protocol
transceivers	I-Protocol
exist	O
supporting	O
synchronous	B-Protocol
optical	I-Protocol
networking	I-Protocol
(	O
SONET	B-Protocol
)	O
,	O
Gigabit	O
Ethernet	O
,	O
Fibre	B-Architecture
Channel	I-Architecture
,	O
PON	B-Architecture
,	O
and	O
other	O
communications	O
standards	O
.	O
</s>
<s>
At	O
introduction	O
,	O
typical	O
speeds	O
were	O
1Gbit/s	O
for	O
Ethernet	O
SFPs	O
and	O
up	O
to	O
4Gbit/s	O
for	O
Fibre	B-Architecture
Channel	I-Architecture
SFP	B-Protocol
modules	I-Protocol
.	O
</s>
<s>
In	O
2006	O
,	O
SFP+	B-Protocol
specification	O
brought	O
speeds	O
up	O
to	O
10Gbit/s	O
and	O
the	O
SFP28	B-Protocol
iteration	O
is	O
designed	O
for	O
speeds	O
of	O
25Gbit/s	O
.	O
</s>
<s>
A	O
slightly	O
larger	O
sibling	O
is	O
the	O
four-lane	O
Quad	B-Protocol
Small	I-Protocol
Form-factor	I-Protocol
Pluggable	I-Protocol
(	O
QSFP	B-Protocol
)	O
.	O
</s>
<s>
In	O
2014	O
,	O
the	O
QSFP28	B-Protocol
variant	O
was	O
published	O
allowing	O
speeds	O
up	O
to	O
100Gbit/s	O
.	O
</s>
<s>
In	O
2019	O
,	O
the	O
closely	O
related	O
QSFP56	B-Protocol
was	O
standardized	O
doubling	O
the	O
top	O
speeds	O
to	O
200Gbit/s	O
with	O
products	O
already	O
selling	O
from	O
major	O
vendors	O
.	O
</s>
<s>
There	O
are	O
inexpensive	O
adapters	O
allowing	O
SFP	B-Protocol
transceivers	I-Protocol
to	O
be	O
placed	O
in	O
a	O
QSFP	B-Protocol
port	O
.	O
</s>
<s>
Both	O
a	O
SFP-DD	O
,	O
which	O
allows	O
for	O
100Gbit/s	O
over	O
two	O
lanes	O
,	O
as	O
well	O
as	O
a	O
QSFP-DD	B-Protocol
specifications	O
,	O
which	O
allows	O
for	O
400Gbit/s	O
over	O
eight	O
lanes	O
,	O
have	O
been	O
published	O
.	O
</s>
<s>
These	O
use	O
a	O
form	O
factor	O
which	O
is	O
directly	O
backward	B-General_Concept
compatible	I-General_Concept
to	O
their	O
respective	O
predecessors	O
.	O
</s>
<s>
An	O
alternative	O
competing	O
solution	O
,	O
the	O
OSFP	B-Protocol
(	O
Octal	O
Small	O
Format	O
Pluggable	O
)	O
has	O
products	O
being	O
released	O
in	O
2022	O
capable	O
of	O
800Gbit/s	O
links	O
between	O
network	B-Device
equipment	I-Device
.	O
</s>
<s>
It	O
is	O
a	O
slightly	O
larger	O
version	O
than	O
the	O
QSFP	B-Protocol
form	O
factor	O
allowing	O
for	O
larger	O
power	O
outputs	O
.	O
</s>
<s>
The	O
OSFP	B-Protocol
standard	O
was	O
initially	O
announced	O
in	O
2016	O
with	O
the	O
4.0	O
version	O
released	O
in	O
2021	O
allowing	O
for	O
800Gbit/s	O
via	O
8×	O
100Gbit/s	O
electrical	O
data	O
lanes	O
.	O
</s>
<s>
Its	O
proponents	O
say	O
a	O
low-cost	O
adapter	O
will	O
allow	O
for	O
backwards	B-General_Concept
compatibility	I-General_Concept
with	O
QSFP	B-Protocol
modules	O
.	O
</s>
<s>
SFP	B-Protocol
transceivers	I-Protocol
are	O
available	O
with	O
a	O
variety	O
of	O
transmitter	O
and	O
receiver	O
specifications	O
,	O
allowing	O
users	O
to	O
select	O
the	O
appropriate	O
transceiver	O
for	O
each	O
link	O
to	O
provide	O
the	O
required	O
optical	O
or	O
electrical	O
reach	O
over	O
the	O
available	O
media	O
type	O
(	O
e.g.	O
</s>
<s>
twisted	O
pair	O
or	O
twinaxial	O
copper	O
cables	O
,	O
multi-mode	B-Device
or	O
single-mode	B-Device
fiber	I-Device
cables	O
)	O
.	O
</s>
<s>
SFP	B-Protocol
modules	I-Protocol
are	O
commonly	O
available	O
in	O
several	O
different	O
categories	O
.	O
</s>
<s>
Note	O
that	O
the	O
QSFP/QSFP	O
+	O
/QSFP28/QSFP56	O
are	O
designed	O
to	O
be	O
electrically	O
backwards	B-General_Concept
compatible	I-General_Concept
with	O
SFP/SFP	O
+	O
/SFP28	O
or	O
SFP56	B-Protocol
respectively	O
.	O
</s>
<s>
Using	O
a	O
simple	O
adapter	O
or	O
a	O
special	O
direct	O
attached	O
cable	O
it	O
is	O
possible	O
to	O
connect	O
those	O
interfaces	O
together	O
using	O
just	O
one	O
lane	O
instead	O
of	O
four	O
provided	O
by	O
the	O
QSFP/QSFP	O
+	O
/QSFP28/QSFP56	O
form	O
factor	O
.	O
</s>
<s>
The	O
same	O
applies	O
to	O
the	O
QSFP-DD	B-Protocol
form	O
factor	O
with	O
8	O
lanes	O
which	O
can	O
work	O
downgraded	O
to	O
4/2/1	O
lanes	O
.	O
</s>
<s>
BX	O
(	O
officially	O
BX10	O
)	O
1550nm/1310nm	O
,	O
Single	O
Fiber	O
Bi-Directional	O
100	O
Mbit	O
SFP	B-Protocol
Transceivers	I-Protocol
,	O
paired	O
as	O
BX-U	O
(	O
)	O
and	O
BX-D	O
(	O
)	O
for	O
uplink	O
and	O
downlink	O
respectively	O
,	O
also	O
for	O
distances	O
up	O
to	O
10km	O
.	O
</s>
<s>
100BASE-TX	B-Protocol
for	O
distances	O
up	O
to	O
100m	O
.	O
</s>
<s>
Other	O
multi-mode	B-Device
SFP	O
applications	O
support	O
even	O
higher	O
rates	O
at	O
shorter	O
distances	O
.	O
</s>
<s>
Based	O
on	O
LX	O
but	O
engineered	O
to	O
work	O
with	O
a	O
multi-mode	B-Device
fiber	I-Device
using	O
a	O
standard	O
multi-mode	B-Device
patch	O
cable	O
rather	O
than	O
a	O
mode-conditioning	O
cable	O
commonly	O
used	O
to	O
adapt	O
LX	O
to	O
multi-mode	B-Device
.	O
</s>
<s>
BX	O
(	O
officially	O
BX10	O
)	O
1490nm/1310nm	O
,	O
Single	O
Fiber	O
Bi-Directional	O
Gigabit	O
SFP	B-Protocol
Transceivers	I-Protocol
,	O
paired	O
as	O
BX-U	O
and	O
BX-D	O
for	O
uplink	O
and	O
downlink	O
respectively	O
,	O
also	O
for	O
distances	O
up	O
to	O
10km	O
.	O
</s>
<s>
1000BASE-Tthese	O
modules	O
incorporate	O
significant	O
interface	O
circuitry	O
for	O
Physical	B-Protocol
Coding	I-Protocol
Sublayer	I-Protocol
recoding	O
and	O
can	O
be	O
used	O
only	O
for	O
gigabit	O
Ethernet	O
because	O
of	O
the	O
specific	O
line	O
code	O
.	O
</s>
<s>
They	O
are	O
not	O
compatible	O
with	O
(	O
or	O
rather	O
:	O
do	O
not	O
have	O
equivalents	O
for	O
)	O
Fibre	B-Architecture
Channel	I-Architecture
or	O
SONET	B-Protocol
.	O
</s>
<s>
Unlike	O
non-SFP	O
,	O
copper	O
1000BASE-T	O
ports	O
integrated	O
into	O
most	O
routers	O
and	O
switches	O
,	O
1000BASE-T	O
SFPs	O
usually	O
cannot	O
operate	O
at	O
100BASE-TX	B-Protocol
speeds	O
.	O
</s>
<s>
100	O
Mbit/s	O
copper	O
and	O
opticalsome	O
vendors	O
have	O
shipped	O
100Mbit/s	O
limited	O
SFPs	O
for	O
fiber-to-the-home	B-Architecture
applications	O
and	O
drop-in	O
replacement	O
of	O
legacy	O
100BASE-FX	O
circuits	O
.	O
</s>
<s>
This	O
was	O
eventually	O
used	O
by	O
both	O
4GFC	B-Architecture
Fibre	B-Architecture
Channel	I-Architecture
and	O
the	O
DDR	O
Infiniband	B-Architecture
especially	O
in	O
its	O
four	O
lane	O
QSFP	B-Protocol
form	O
.	O
</s>
<s>
In	O
recent	O
years	O
,	O
SFP	B-Protocol
transceivers	I-Protocol
have	O
been	O
created	O
that	O
will	O
allow	O
2.5	O
Gbit/s	O
and	O
5	O
Gbit/s	O
Ethernet	O
speeds	O
with	O
SFPs	O
with	O
2.5GBASE-T	O
and	O
5GBASE-T	O
.	O
</s>
<s>
The	O
SFP+	B-Protocol
(	O
enhanced	O
small	B-Protocol
form-factor	I-Protocol
pluggable	I-Protocol
)	O
is	O
an	O
enhanced	O
version	O
of	O
the	O
SFP	O
that	O
supports	O
data	O
rates	O
up	O
to	O
16Gbit/s	O
.	O
</s>
<s>
The	O
SFP+	B-Protocol
specification	O
was	O
first	O
published	O
on	O
May	O
9	O
,	O
2006	O
,	O
and	O
version	O
4.1	O
published	O
on	O
July	O
6	O
,	O
2009	O
.	O
</s>
<s>
SFP+	B-Protocol
supports	O
8Gbit/s	O
Fibre	B-Architecture
Channel	I-Architecture
,	O
10	O
Gigabit	O
Ethernet	O
and	O
Optical	B-Protocol
Transport	I-Protocol
Network	I-Protocol
standard	O
OTU2	B-Protocol
.	O
</s>
<s>
Although	O
the	O
SFP+	B-Protocol
standard	O
does	O
not	O
include	O
mention	O
of	O
16Gbit/s	O
Fibre	B-Architecture
Channel	I-Architecture
,	O
it	O
can	O
be	O
used	O
at	O
this	O
speed	O
.	O
</s>
<s>
Besides	O
the	O
data	O
rate	O
,	O
the	O
major	O
difference	O
between	O
8	O
and	O
16Gbit/s	O
Fibre	B-Architecture
Channel	I-Architecture
is	O
the	O
encoding	O
method	O
.	O
</s>
<s>
64b/66b	O
encoding	O
used	O
for	O
"	O
16Gbit/s	O
"	O
is	O
a	O
more	O
efficient	O
encoding	O
mechanism	O
than	O
8b/10b	B-Protocol
used	O
for	O
8Gbit/s	O
,	O
and	O
allows	O
for	O
the	O
data	O
rate	O
to	O
double	O
without	O
doubling	O
the	O
line	O
rate	O
.	O
</s>
<s>
16GFC	B-Architecture
does	O
n't	O
really	O
use	O
16	O
Gbit/s	O
signaling	O
anywhere	O
.	O
</s>
<s>
It	O
uses	O
a	O
14.025Gbit/s	O
line	O
rate	O
to	O
achieve	O
twice	O
the	O
throughput	O
of	O
8GFC	B-Architecture
.	O
</s>
<s>
SFP+	B-Protocol
also	O
introduces	O
direct	O
attach	O
for	O
connecting	O
two	O
SFP+	B-Protocol
ports	O
without	O
dedicated	O
transceivers	O
.	O
</s>
<s>
10Gbit/s	O
SFP+	B-Protocol
modules	O
are	O
exactly	O
the	O
same	O
dimensions	O
as	O
regular	O
SFPs	O
,	O
allowing	O
the	O
equipment	O
manufacturer	O
to	O
re-use	O
existing	O
physical	O
designs	O
for	O
24	O
and	O
48-port	O
switches	O
and	O
modular	O
line	O
cards	O
.	O
</s>
<s>
In	O
comparison	O
to	O
earlier	O
XENPAK	B-Protocol
or	O
XFP	B-Protocol
modules	O
,	O
SFP+	B-Protocol
modules	O
leave	O
more	O
circuitry	O
to	O
be	O
implemented	O
on	O
the	O
host	O
board	O
instead	O
of	O
inside	O
the	O
module	O
.	O
</s>
<s>
Through	O
the	O
use	O
of	O
an	O
active	O
electronic	O
adapter	O
,	O
SFP+	B-Protocol
modules	O
may	O
be	O
used	O
in	O
older	O
equipment	O
with	O
XENPAK	B-Protocol
ports	O
and	O
X2	B-Device
ports	O
.	O
</s>
<s>
SFP+	B-Protocol
modules	O
can	O
be	O
described	O
as	O
limiting	O
or	O
linear	O
types	O
;	O
this	O
describes	O
the	O
functionality	O
of	O
the	O
inbuilt	O
electronics	O
.	O
</s>
<s>
Limiting	O
SFP+	B-Protocol
modules	O
include	O
a	O
signal	O
amplifier	O
to	O
re-shape	O
the	O
(	O
degraded	O
)	O
received	O
signal	O
whereas	O
linear	O
ones	O
do	O
not	O
.	O
</s>
<s>
SFP28	B-Protocol
is	O
a	O
25Gbit/s	O
interface	O
which	O
evolved	O
from	O
the	O
100	B-Protocol
Gigabit	I-Protocol
Ethernet	I-Protocol
interface	O
which	O
is	O
typically	O
implemented	O
with	O
4	O
by	O
25Gbit/s	O
data	O
lanes	O
.	O
</s>
<s>
Identical	O
in	O
mechanical	O
dimensions	O
to	O
SFP	O
and	O
SFP+	B-Protocol
,	O
SFP28	B-Protocol
implements	O
one	O
28Gbit/s	O
lane	O
accommodating	O
25Gbit/s	O
of	O
data	O
with	O
encoding	O
overhead	O
.	O
</s>
<s>
SFP28	B-Protocol
modules	O
exist	O
supporting	O
single	O
-	O
or	O
multi-mode	B-Device
fiber	I-Device
connections	O
,	O
active	O
optical	O
cable	O
and	O
direct	O
attach	O
copper	O
.	O
</s>
<s>
The	O
compact	O
small	B-Protocol
form-factor	I-Protocol
pluggable	I-Protocol
(	O
cSFP	O
)	O
is	O
a	O
version	O
of	O
SFP	O
with	O
the	O
same	O
mechanical	O
form	O
factor	O
allowing	O
two	O
independent	O
bidirectional	O
channels	O
per	O
port	O
.	O
</s>
<s>
The	O
small	B-Protocol
form-factor	I-Protocol
pluggable	I-Protocol
double	O
density	O
(	O
SFP-DD	O
)	O
multi	O
source	O
agreement	O
is	O
a	O
standard	O
published	O
in	O
2019	O
for	O
doubling	O
port	O
density	O
.	O
</s>
<s>
According	O
to	O
the	O
SFD-DD	O
MSA	O
website	O
:	O
"	O
Network	B-Device
equipment	I-Device
based	O
on	O
the	O
SFP-DD	O
will	O
support	O
legacy	O
SFP	B-Protocol
modules	I-Protocol
and	O
cables	O
,	O
and	O
new	O
double	O
density	O
products.	O
"	O
</s>
<s>
Quad	B-Protocol
Small	I-Protocol
Form-factor	I-Protocol
Pluggable	I-Protocol
(	O
QSFP	B-Protocol
)	O
transceivers	O
are	O
available	O
with	O
a	O
variety	O
of	O
transmitter	O
and	O
receiver	O
types	O
,	O
allowing	O
users	O
to	O
select	O
the	O
appropriate	O
transceiver	O
for	O
each	O
link	O
to	O
provide	O
the	O
required	O
optical	O
reach	O
over	O
multi-mode	B-Device
or	O
single-mode	B-Device
fiber	I-Device
.	O
</s>
<s>
4	O
Gbit/s	O
The	O
original	O
QSFP	B-Protocol
document	O
specified	O
four	O
channels	O
carrying	O
Gigabit	O
Ethernet	O
,	O
4GFC	B-Architecture
(	O
FiberChannel	B-Architecture
)	O
,	O
or	O
DDR	O
InfiniBand	B-Architecture
.	O
</s>
<s>
40	O
Gbit/s	O
(	O
QSFP+	B-Protocol
)	O
QSFP+	B-Protocol
is	O
an	O
evolution	O
of	O
QSFP	B-Protocol
to	O
support	O
four	O
10Gbit/s	O
channels	O
carrying	O
10	O
Gigabit	O
Ethernet	O
,	O
10GFC	B-Architecture
FiberChannel	B-Architecture
,	O
or	O
QDR	O
InfiniBand	B-Architecture
.	O
</s>
<s>
The	O
4	O
channels	O
can	O
also	O
be	O
combined	O
into	O
a	O
single	O
40	B-Protocol
Gigabit	I-Protocol
Ethernet	I-Protocol
link	O
.	O
</s>
<s>
50	O
Gbit/s	O
(	O
QSFP14	O
)	O
The	O
QSFP14	O
standard	O
is	O
designed	O
to	O
carry	O
FDR	O
InfiniBand	B-Architecture
,	O
SAS-3	O
.	O
</s>
<s>
100	O
Gbit/s	O
(	O
QSFP28	B-Protocol
)	O
The	O
QSFP28	B-Protocol
standard	O
is	O
designed	O
to	O
carry	O
100	B-Protocol
Gigabit	I-Protocol
Ethernet	I-Protocol
,	O
EDR	O
InfiniBand	B-Architecture
,	O
or	O
32G	O
Fibre	B-Architecture
Channel	I-Architecture
.	O
</s>
<s>
Sometimes	O
this	O
transceiver	O
type	O
is	O
also	O
referred	O
to	O
as	O
"	O
QSFP100	O
"	O
or	O
"	O
100G	B-Protocol
QSFP	B-Protocol
"	O
for	O
sake	O
of	O
simplicity	O
.	O
</s>
<s>
200	O
Gbit/s	O
(	O
QSFP56	B-Protocol
)	O
QSFP56	B-Protocol
is	O
designed	O
to	O
carry	O
200	B-Protocol
Gigabit	I-Protocol
Ethernet	I-Protocol
,	O
HDR	O
InfiniBand	B-Architecture
,	O
or	O
64G	O
Fibre	B-Architecture
Channel	I-Architecture
.	O
</s>
<s>
The	O
biggest	O
enhancement	O
is	O
that	O
QSFP56	B-Protocol
uses	O
four-level	O
pulse-amplitude	O
modulation	O
(	O
PAM-4	O
)	O
instead	O
of	O
non-return-to-zero	B-Protocol
(	O
NRZ	O
)	O
.	O
</s>
<s>
It	O
uses	O
the	O
same	O
physical	O
specifications	O
as	O
QSFP28	B-Protocol
(	O
SFF-8665	O
)	O
,	O
with	O
electrical	O
specifications	O
from	O
SFF-8024	O
and	O
revision	O
2.10a	O
of	O
SFF-8636	O
.	O
</s>
<s>
Sometimes	O
this	O
transceiver	O
type	O
is	O
referred	O
to	O
as	O
"	O
200G	B-Protocol
QSFP	B-Protocol
"	O
for	O
sake	O
of	O
simplicity	O
.	O
</s>
<s>
Switch	O
and	O
router	O
manufacturers	O
implementing	O
QSFP+	B-Protocol
ports	O
in	O
their	O
products	O
frequently	O
allow	O
for	O
the	O
use	O
of	O
a	O
single	O
QSFP+	B-Protocol
port	O
as	O
four	O
independent	O
10	O
gigabit	O
ethernet	O
connections	O
,	O
greatly	O
increasing	O
port	O
density	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
typical	O
24-port	O
QSFP+	B-Protocol
1U	B-Application
switch	O
would	O
be	O
able	O
to	O
service	O
96x10GbE	O
connections	O
.	O
</s>
<s>
There	O
also	O
exist	O
fanout	O
cables	O
to	O
adapt	O
a	O
single	O
QSFP28	B-Protocol
port	O
to	O
four	O
independent	O
25	B-Protocol
gigabit	I-Protocol
ethernet	I-Protocol
SFP28	B-Protocol
ports	O
(	O
QSFP28-to-4	O
×SFP28	O
)	O
as	O
well	O
as	O
cables	O
to	O
adapt	O
a	O
single	O
QSFP56	B-Protocol
port	O
to	O
four	O
independent	O
50	B-Protocol
gigabit	I-Protocol
ethernet	I-Protocol
SFP56	B-Protocol
ports	O
(	O
QSFP56-to-4	O
×SFP56	O
)	O
.	O
</s>
<s>
SFP	O
sockets	O
are	O
found	O
in	O
Ethernet	B-Protocol
switches	I-Protocol
,	O
routers	O
,	O
firewalls	O
and	O
network	B-Protocol
interface	I-Protocol
cards	I-Protocol
.	O
</s>
<s>
They	O
are	O
used	O
in	O
Fibre	B-Architecture
Channel	I-Architecture
host	B-Architecture
adapters	I-Architecture
and	O
storage	O
equipment	O
.	O
</s>
<s>
Because	O
of	O
their	O
low	O
cost	O
,	O
low	O
profile	O
,	O
and	O
ability	O
to	O
provide	O
a	O
connection	O
to	O
different	O
types	O
of	O
optical	B-Architecture
fiber	I-Architecture
,	O
SFP	O
provides	O
such	O
equipment	O
with	O
enhanced	O
flexibility	O
.	O
</s>
<s>
The	O
SFP	B-Protocol
transceiver	I-Protocol
is	O
not	O
standardized	O
by	O
any	O
official	O
standards	O
body	O
,	O
but	O
rather	O
is	O
specified	O
by	O
a	O
multi-source	O
agreement	O
(	O
MSA	O
)	O
among	O
competing	O
manufacturers	O
.	O
</s>
<s>
The	O
SFP	O
was	O
designed	O
after	O
the	O
GBIC	B-Protocol
interface	O
,	O
and	O
allows	O
greater	O
port	O
density	O
(	O
number	O
of	O
transceivers	O
per	O
given	O
area	O
)	O
than	O
the	O
GBIC	B-Protocol
,	O
which	O
is	O
why	O
SFP	O
is	O
also	O
known	O
as	O
mini-GBIC	B-Protocol
.	O
</s>
<s>
However	O
,	O
as	O
a	O
practical	O
matter	O
,	O
some	O
networking	B-Device
equipment	I-Device
manufacturers	O
engage	O
in	O
vendor	O
lock-in	O
practices	O
whereby	O
they	O
deliberately	O
break	O
compatibility	O
with	O
"	O
generic	O
"	O
SFPs	O
by	O
adding	O
a	O
check	O
in	O
the	O
device	O
's	O
firmware	B-Application
that	O
will	O
enable	O
only	O
the	O
vendor	O
's	O
own	O
modules	O
.	O
</s>
<s>
Third-party	O
SFP	O
manufacturers	O
have	O
introduced	O
SFPs	O
with	O
EEPROMs	B-General_Concept
which	O
may	O
be	O
programmed	O
to	O
match	O
any	O
vendor	O
ID	O
.	O
</s>
<s>
SFP	B-Protocol
transceivers	I-Protocol
are	O
'	O
right-handed	O
'	O
:	O
From	O
their	O
perspective	O
,	O
they	O
transmit	O
on	O
the	O
right	O
and	O
receive	O
on	O
the	O
left	O
.	O
</s>
<s>
The	O
SFP	B-Protocol
transceiver	I-Protocol
contains	O
a	O
printed	O
circuit	O
board	O
with	O
an	O
edge	O
connector	O
with	O
20	O
pads	O
that	O
mate	O
on	O
the	O
rear	O
with	O
the	O
SFP	O
electrical	O
connector	O
in	O
the	O
host	O
system	O
.	O
</s>
<s>
The	O
QSFP	B-Protocol
has	O
38	O
pads	O
including	O
4	O
high-speed	O
transmit	O
data	O
pairs	O
and	O
4	O
high-speed	O
receive	O
data	O
pairs	O
.	O
</s>
<s>
+SFP	O
electrical	O
pin-out	O
Pad	O
Name	O
Function	O
1	O
VeeT	O
Transmitter	O
ground	O
2	O
Tx_Fault	O
Transmitter	O
fault	O
indication	O
3	O
Tx_Disable	O
Optical	O
output	O
disabled	O
when	O
high	O
4	O
SDA	O
2-wire	O
serial	O
interface	O
data	O
line	O
(	O
using	O
the	O
CMOS	B-Device
EEPROM	B-General_Concept
protocol	O
defined	O
for	O
the	O
ATMEL	O
AT24C01A/02/04	O
familyINF-8074i	O
B4	O
)	O
5	O
SCL	O
2-wire	O
serial	O
interface	O
clock	O
6	O
Mod_ABS	O
Module	O
absent	O
,	O
connection	O
to	O
VeeT	O
or	O
VeeR	O
in	O
the	O
module	O
indicates	O
module	O
presence	O
to	O
host	O
7	O
RS0	O
Rate	O
select	O
0	O
8	O
Rx_LOS	O
Receiver	O
loss	O
of	O
signal	O
indication	O
9	O
RS1	O
Rate	O
select	O
1	O
10	O
VeeR	O
Receiver	O
ground	O
11	O
VeeR	O
Receiver	O
ground	O
12	O
RD	O
-	O
Inverted	O
received	O
data	O
13	O
RD+	O
Received	O
data	O
14	O
VeeR	O
Receiver	O
ground	O
15	O
VccR	O
Receiver	O
power	O
(	O
3.3	O
V	O
,	O
max	O
.	O
</s>
<s>
The	O
physical	O
dimensions	O
of	O
the	O
SFP	B-Protocol
transceiver	I-Protocol
(	O
and	O
its	O
subsequent	O
faster	O
variants	O
)	O
are	O
narrower	O
than	O
the	O
later	O
QSFP	B-Protocol
counterparts	O
,	O
which	O
allows	O
for	O
SFP	B-Protocol
transceivers	I-Protocol
to	O
be	O
placed	O
in	O
QSFP	B-Protocol
ports	O
via	O
an	O
inexpensive	O
adapter	O
.	O
</s>
<s>
Both	O
are	O
smaller	O
than	O
the	O
XFP	B-Protocol
transceiver	I-Protocol
.	O
</s>
<s>
The	O
SFP	O
MSA	O
defines	O
a	O
256-byte	O
memory	O
map	O
into	O
an	O
EEPROM	B-General_Concept
describing	O
the	O
transceiver	O
's	O
capabilities	O
,	O
standard	O
interfaces	O
,	O
manufacturer	O
,	O
and	O
other	O
information	O
,	O
which	O
is	O
accessible	O
over	O
a	O
serial	O
I²C	O
interface	O
at	O
the	O
8-bit	O
address	O
0b1010000X	O
(	O
0xA0	O
)	O
.	O
</s>
<s>
Modern	O
optical	O
SFP	B-Protocol
transceivers	I-Protocol
support	O
standard	O
digital	O
diagnostics	O
monitoring	O
(	O
DDM	O
)	O
functions	O
.	O
</s>
<s>
In	O
network	B-Device
equipment	I-Device
,	O
this	O
information	O
is	O
typically	O
made	O
available	O
via	O
Simple	B-Protocol
Network	I-Protocol
Management	I-Protocol
Protocol	I-Protocol
(	O
SNMP	B-Protocol
)	O
.	O
</s>
<s>
A	O
DDM	O
interface	O
allows	O
end	O
users	O
to	O
display	O
diagnostics	O
data	O
and	O
alarms	O
for	O
optical	B-Architecture
fiber	I-Architecture
transceivers	O
and	O
can	O
be	O
used	O
to	O
diagnose	O
why	O
a	O
transceiver	O
is	O
not	O
working	O
.	O
</s>
