2: Functional Description
PremierWave® 2050 Through-Hole Adapter Integration Guide
18
Table 2-6 Example RS422/485 Connections (Serial Transceiver Required)
PremierWave
2050 Signal
(logic)
Description
RS485
Signal
DB25 4
Wire
DB25 2
Wire
DB9 4
wire
DB9 2
wire
TXDx
Data Out
TX+485
14
14
7
7
TXDx
Data Out
TX-485
15
15
3
3
RXDx
Data In
RX+485
21
14
2
7
RXDx
Data In
RX-485
22
15
8
3
RTSx
TX Enable
CPx
RS485 Select
CPy
RS485 2-wire
Note:
The IO pins for PremierWave 2050 are set to floating input on power up until
configured by unit firmware. An external 100K ohm pull-up may be required on the serial
transmit signal to prevent downstream UART devices from detecting false characters on
initial power up.
Ethernet Interface
The PremierWave 2050 provides a 10/100 Mbps Ethernet interface for connection to an
external network through external magnetics and an external RJ45. The figure below shows
the Ethernet connections to a 10/100 Ethernet RJ45 Jack with Magnetics, J5 in the figure. The
BELFUSE RJ45 magnetic jack is part number 08B0-1D1T-06-F.
The Ethernet differential pair signals, ERXM/ERXP and ETXM/ETXP should be routed as 100-
ohm differential pairs on a layer next to the signal ground plane. The use of vias on these
signals should be minimized. Center tap signals RXCT and TXCT should be routed with at
least 20 mil trace thickness. The area underneath the RJ45 magnetic jack should be void of all
signals and planes. The connector shield should be connected to chassis. It is recommended
that 1206 resistor pads from chassis ground to signal ground be placed next to each of the
shield tabs. The resistor pads allow for 0 ohm jumper, ferrite beads, or decoupling caps to be
installed as needed for EMI/EMC improvement.
The Ethernet LED signals should be routed to discrete LEDs or to the LED pins on the RJ45
through 220 ohm or larger resistors. The LED signals are active low.
Also shown in the figure is an optional active choke that can be used to improve ESD, EFT,
and EMI/EMC performance in harsh environments. The device is shown as U22 in the figure
and is made by Akros Silicon, part number AS1602. This device features route through pin
assignments allowing for the Ethernet differential signal pairs to be routed without altering the
trace impedance or adding vias. Due to this routing the device could be installed or
depopulated as needed. Lantronix has performed all certification to FCC Class B without U22
populated.
The Ethernet signals may be left disconnected if unused.
