Cooper Bussmann 945U-E User Manual Download Page 39

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Cooper Bussmann 945U-E Wireless Ethernet Modem & Device Server User Manual

Rev Version 2.14

For example, if the interfering noise levels are around -80 dB you can raise the noise floor to -70 dB to block out
any signals below, making sure that the RSSI levels of any connected modules are not below this noise floor as
they will not communicate. The Connectivity page can be used to determine if other systems are in the area and
their RSSI levels.

After configuring the fixed noise floor, confirm that the channel utilization has dropped to a desirable level and
where possible perform an Iperf throughput test to confirm acceptable performance.

3.10 Serial Port Configuration

The 945U-E has an RS-232 and an RS-485 port for serial communications. These ports may be used for different
purposes. The 945U-E offers three serial functions—PPP server, serial gateway, and Modbus TCP to RTU gateway.

RS-232 PPP Server

The 945U-E can be used as a PPP (Point-to-Point Protocol) server to connect the wireless system to serial devices
via the RS232 or RS485 serial ports. PPP server enables a network connection to the 945U-E over a serial cable.
This is much like dial up Internet. The maximum serial data rate is 115,200 bps. Hardware or software flow control
may be selected. With minimal configuration on the PC, you may use dial-up networking in Windows XP to connect
to the network via the serial port.

For the 945U-E, users must configure the local IP address for the 945U-E and the remote device IP address. Some
care must be taken in selecting these IP addresses.

• If you want to use routing over this serial network connection, the IP addresses selected must not lie on

wireless or wired Ethernet networks already configured into the device. You must ensure they set routing rules
appropriately for devices either side of the network.

• If you want the serial device visible as present on the wireless or wired network, then the local IP address must

be the same as the IP address set for the desired port. A process called “proxy ARP” is used to make the
device visible on the network. In this process, the 945U-E pretends that it holds the IP address on the network,
and responds on behalf of the remote device.

The result of this is similar to bridging for a single device, with some exceptions. One of these exceptions is the
inability to handle name server searches of the network via this serial link. For example, you would encounter
difficulty if you were to use Windows Explorer over the serial link to find a PC on the wired network. For this to
operate correctly you must explicitly map computer names to IP addresses in the LMHOSTS file on your PC.

To configure Windows XP to establish a PPP connection to a 945U-E in SETUP mode:

1. On

Network Connections

, select “Create a new connection.”

2. In the New Connection Wizard, click

3. Set up an advanced connection.

4. Connect directly to another computer.

5. Set the PC as guest.

6. Set the Connection Name.

7. Select a COM port.

8. Select availability.

9. Click