4
1. Functional description
The 10/100BASE-T(X) ports of an RS2-TX
represent a terminal connection for the
connected LAN segment. You can connect
single devices or complete network seg-
ments.
1.1 FRAME SWITCHING FUNCTIONS
Store and Forward
All data received by the RS2-TX from the
system bus or at the ports are stored and
checked for validity. Invalid and defective
frames (> 1.522 byte or CRC error) as well
as fragments (< 64 byte) are discarded. The
RS2-TX forwards the valid frames.
Multi address capability
An RS2-TX 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.
An RS2-TX 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 independent sub-
networks can be connected to an RS2-TX.
Learnt addresses
An RS2-TX monitors the age of the learned
addresses. The RS2-TX 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 VLAN tag are
transmitted unchanged by the RS2-TX.
1.2 SPECIFIC FUNCTIONS OF THE
TP/TX INTERFACE
Link control
The RS2-TX monitors the connected TP/TX
line segments for short-circuit or interrupt
using regular link test pulses in accordance
with IEEE standard 802.3 10/100BASE-T/TX.
The RS2-TX does not transmit any data to a
TP/TX segment from which it does not
receive a link test pulse.
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 link
test pulses.
Auto polarity exchange
If the receive line pair is incorrectly connec-
ted (RD+ and RD- switched) polarity is auto-
matically reversed.
Autocrossing
The RS2-TX detects the transmit and re-
ceive pairs (MDI, MDI-X). The RS2-TX auto-
matically configures its port for the correct
transmit and receive pins. Consequently it
does not matter whether you connect devi-
ces using a cross-over or straight cable.
1.3 FURTHER FUNCTIONS
AND FEATURES
Reset
The RS2-TX will be reset by the following
action:
– input voltages fall below a threshold
After a reset the following action is carried
through:
– initialization
1.4 DISPLAY ELEMENTS
Equipment status
These LEDs provide information about sta-
tuses which affect the function of the entire
RS2-TX.
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 – Failure
(red LED)
– lit:
– The indicator contact is
open, i.e. it indicates an
error.
– not lit:
– The indicator contact is
closed, i.e. it does not
indicate an error.
Port Status
These LEDs display port-related informati-
on.
DA/STAT 1 to 8 – Data, Link status
(green/yellow LED)
– not lit:
– no valid link
– lit green:
– valid link
– flashes yellow:– receiving data
1.5 CONTROLS
8-pin DIP switch
Using the 8-pin DIP switch on the RS2-TX
front panel
– the message about the link statuses can
be suppressed by the indicator contact on
a port-by-port basis. Using switches
LA1
to
LA8
, the message about the link status
of ports 1 to 8 is suppressed. State on deli-
very: switch position 1 (on), i.e. message
not suppressed.
Fig. 2: 8-pin DIP switch on RS2-TX
1.6 INTERFACES
10/100 MBit/s connection
Eight 10/100 Mbit Ports (ports 1 to port 8, 8-
pin R45 sockets) on RS2-TX allow terminal
equipment or eight independent network
segments complying with the standards
IEEE 802.3 100BASE-TX / 10BASE-T to be
connected. These ports support autonego-
tiation and the autopolarity function.
The socket casings are electrically connec-
ted to the front panel of the RS2-TX.The pin
configuration complies with MDI-X.
– Pin configuration
of the RJ45 socket:
– 1 line pair: pin 3 and pin 6
– 1 line pair: pin 1 and pin 2
– remaining pins: not used.
Fig. 3: Pin configuration of an TP/TX
interface
Pin 8
Pin 7
Pin 6
Pin 5
Pin 4
Pin 3
Pin 2
Pin 1
LA1
LA6
0
1
LA5
LA3
LA2
LA4
Port 1
Port 6
Port 5
Port 3
Port 2
Port 4
Suppress message
about link status
via indicator contact
LA7
LA8
Port 7
Port 8
5
i
RS2-TX
+24V
+24V*
FAUL
T
LA1
LA3
LA2
LA4
LA5
LA6
0 1
6
7
8
DA/STAT
1
3
2
4
6
8
5
FAULT
1
2
LA7
LA8
7
P
1
2
3
4
5-pin
terminal
block
LED display
elements
8-pin
DIP switch
8 ports 10/100BASE-T(X)
(ports 1 to 8), RJ45 connectors
autonegotiaton, autopolarity,
autocrossing
Fiig. 1: Overview interfaces, display elements and controls of the RS2-TX
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