2000, 2001 Cirronet
Incorporated
2
M-2410-0007 Rev -
Getting Started
The SEM family of wireless Ethernet modems are easy to install and operate. In most
instances, the only installation steps will be setting IP addresses, selecting one modem as
the master and connecting the antenna, power and Ethernet cable.
Connecting the SEM
Figure 1 identifies the various connectors on the rear of the SEM.
Figure 1. SEM Rear Panel Diagram
The antenna connector is a TNC type connector. An antenna may be connected directly
to this connector. Alternatively, an antenna may be located away from the SEM using RF
cable to connect the SEM to the antenna. Cirronet does not recommend using RF cables
longer than 5 feet. If more distance is required between the SEM and the antenna, high-
quality, low-loss RF feed line must be used. Alternatively, the SEM2410X has a remote
radio assembly that is mounted next to the antenna. The remote radio assembly is
connected to the SEM through a baseband cable that can be ordered in 100 foot
increments up to 500 feet in length. The SEM2410X has a 15 pin connector in place of
the TNC connector on the SEM2410.
The 10BaseT Ethernet connector is the standard RJ-45 connector. The connector is wired
to be able to connect directly to an Ethernet device using a straight-through cable without
having to connect through a hub. If it is desired to connect the SEM to a hub, the SEM
must be connected to the Uplink port of the hub to use a straight-through cable.
Otherwise a cross-over cable is needed to connect a SEM to a hub. The Ethernet
connector has two LEDs built in. The green LED on the left indicates a good Ethernet
connection. The yellow LED on the right indicates network collisions. When the yellow
LED is on continuously, it indicates that there is sufficient network congestion to impact
data throughput.
The synchronizing signals are provided for special applications where multiple master
SEMs are co-located. The synchronizing signals are RS-485 levels and may be connected
Power Connector
Synchronizing Signals
10BaseT Ethernet Connector
TNC Antenna Connector
Ethernet Link
Ethernet Collision
