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1. Functional description
The 10/100BASE-T(X) ports of a RS2-
xTX/xFX EEC represent a terminal connec-
tion for the connected LAN segment. You
can connect single devices or complete net-
work segments.
1.1 FRAME SWITCHING FUNCTIONS
Store and Forward
All data received by the RS2-xTX/xFX EEC
from the system bus or at the ports is
stored and checked for validity. Frames
> 1536 bytes as well as fragments (< 64
bytes) are discarded. The RS2-xTX/xFX EEC
forwards the valid frames.
Multi address capability
A RS2-xTX/xFX EEC learns all source
addresses per port. Only packets with
– unknown addresses
– addresses learnt at this port
– a multi/broadcast address
in the destination address field are sent to
this port.
A RS2-xTX/xFX EEC learns up to 1,000
addresses. This becomes necessary if more
than one terminal device is connected to
one or more ports. In this way several inde-
pendent subnetworks can be connected to a
RS2-xTX/xFX EEC.
Learnt addresses
A RS2-xTX/xFX EEC monitors the age of the
learned addresses. The RS2-xTX/xFX EEC
deletes address entries from the address
table which exceed a certain age (300
seconds).
Note:
Restarting deletes the learned
address entries.
Tagging
(IEEE 802.1Q)
The IEEE 802.1 Q standard designates the
VLAN tag to be included in a MAC data
frame for the VLAN and prioritizing func-
tions. The VLAN tag consists of 4 bytes (2
bytes tag protocol identifier TPID, 2 bytes
tag control information TCI). It is inserted
between the source address field and the
type field. Data packets with a VLAN tag are
transmitted unchanged by the RS2-xTX/xFX
EEC.
1.2 SPECIFIC FUNCTIONS OF THE
TP/TX INTERFACE
Link control
The RS2-xTX/xFX EEC monitors the connec-
ted TP/TX line segments for short-circuits or
interrupts using regular Idle signals in
accordance with IEEE standard 802.3
10/100BASE-T/TX. The RS2-xTX/xFX EEC
does not transmit any data to a TP/TX seg-
ment from which it does not receive an Idle
signal.
Note:
A non-occupied interface is assessed
as a line interrupt. The TP/TX line to termi-
nal equipment which is switched off is like-
wise assessed as a line interrupt as the de-
energised bus coupler cannot transmit Idle
signals.
Auto polarity exchange
If the receive line pair is incorrectly connec-
ted (RD+ and RD- switched) polarity is auto-
matically reversed.
Autocrossing
The RS2-xTX/xFX EEC detects the transmit
and receive pairs (MDI, MDI-X). The
RS2-xTX/xFX EEC automatically con-
figures its port for the correct transmit and
receive pins. Consequently it does not
matter whether you connect devices using
a cross-over or straight cable.
1.3 SPECIFIC FUNCTIONS OF THE
F/O INTERFACE
Link control
The RS2-xTX/xFX EEC monitors the connec-
ted F/O line for interrupts using idle signals
during frame pauses in accordance with
IEEE standard 802.3 100BASE-FX. The
RS2-xTX/xFX EEC transmits no data to a F/O
line from which it is receiving no idle signal.
Low Light Detection
If the optical input power decreases below
the low light threshold the transmit and
receive path will be disabled for data and
the idle signal will be transmitted.
Far-End Fault
The optical transmission distance of the
RS2-xTX/xFX EEC can be monitored in
receiving direction as well as in transmitting
direction, if the other side also supports Far-
End Fault. If the other side does not support
Far-End Fault, the optical transmission
distance is monitored only in receiving
direction.
Far-End Fault is sent, if the optical input
power at the optical port has fallen under
the low light level. If Far-End Fault is re-
ceived, the link stays inactive (DA/STAT LED
dark).
1.4 FURTHER FUNCTIONS
AND FEATURES
Reset
The RS2-xTX/xFX EEC will be reset by the
following action:
– input voltages fall below a threshold
After a reset the following action is carried
out:
– initialization
1.5 DISPLAY ELEMENTS
Equipment status
These LEDs provide information about sta-
tuses which affect the function of the entire
RS2-xTX/xFX EEC.
P1 – Power 1
(green LED)
– lit:
– supply voltage 1 present
– not lit: – supply voltage 1 less than 9.6 V
P2 – Power 2
(green LED)
– lit:
– supply voltage 2 present
– not lit: – supply voltage 2 less than 9.6 V
FAULT
(Red LED)
– lit:
– Indicator contact indicates an
error
– lit:
– no error
Port Status
These LEDs display port-related informa-
tion.
DA/STAT 1 to 5,
DA/STAT 1 to 4
(on RS2-4TX EEC)
– Data, Link status
(green LED)
– not lit:
– no valid link
– flashes:
– data activity
– lit:
– valid link
Fig. 1: Overview display elements and interfaces of the RS2-xTX/xFX EEC
3
RS2-3TX/2FX
+24V
+24V*
FA
U
LT
2
3
4
LA1
LA3
LA2
LA4
LA5
0 1
DA/STAT
1
2
5
P
1
2
4
x
1
5
DA/STAT
FAULT
RS2-3TX/2FX EEC
RS2-3TX/2FX-SM EEC
3
RS2-4TX
+24V
+24V*
FA
U
LT
2
3
4
LA1
LA3
LA2
LA4
0 1
DA/STAT
1
2
P
1
2
4
x
1
DA/STAT
FAULT
RS2-4TX EEC
3
RS2-4TX/1FX
+24V
+24V*
FA
U
LT
2
3
4
LA1
LA3
LA2
LA4
LA5
0 1
DA/STAT
1
2
5
P
1
2
4
x
1
5
DA/STAT
FAULT
RS2-4TX/1FX EEC
RS2-4TX/1FX-SM EEC
3
RS2-4TX/1FX
+24V
+24V*
FA
U
LT
2
3
4
LA1
LA3
LA2
LA4
LA5
0 1
DA/STAT
1
2
5
P
1
2
4
x
1
DA/STAT
FAULT
RS2-4TX/1FX-ST EEC
5-pin pluggable terminal block
LED display elements
5-pin DIP switch
3 Ports in line with 10/100BASE-T(X)
(RJ45 connectors)
According to product type:
- up to 1 port in line with 10/100BASE-T(X)
(RJ45 connector)
- up to 2 ports in line with 100BASE-FX
(Duplex SC or ST connector)
full duplex
All ports: autonegotiation, autopolarity
and autocrossing
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