> Ethernet Interface Connection and Setup
> The Site Master S331L fully supports the IEEE-802.3 standard. Most Site Master functions (except power On/Off) can be controlled via an Ethernet connection to a PC that is connected directly (with an Ethernet cross-over cable) or through a network.
> Ethernet networking uses a bus or star topology in which all of the interfacing devices are connected to a central cable called the bus, or are connected to a hub. Ethernet uses the CSMA/CD access method to handle simultaneous transmissions over the bus. CSMA/CD stands for Carrier Sense Multiple Access/Collision Detection. This standard enables network devices to detect simultaneous data channel usage (called a collision) and provides for a contention protocol. When a network device detects a collision, the CSMA/CD standard dictates that the data is retransmitted after waiting a random amount of time. If a second collision is detected, then the data are again retransmitted after waiting twice as long. This is known as exponential back off.
> The TCP/IP setup requires the following:

> • | USB-to-Ethernet Dongle: The S331L requires the use of an external USB-to-Ethernet dongle, such as Anritsu part number 2000‑1810‑R, to enable TCP/IP communication.

> • | IP Address: Every computer/electronic device in a TCP/IP network requires an IP address. An IP address has four numbers (each between 0 and 255) separated by periods. For example: 128.111.122.42 is a valid IP address.

> • | Subnet Mask: The subnet mask distinguishes the portion of the IP address that is the network ID from the portion that is the station ID. The subnet mask 255.255.0.0, when applied to the IP address given above, would identify the network ID as 128.111 and the station ID as 122.42. All stations in the same local area network should have the same network ID, but different station IDs.

> • | Default Gateway: A TCP/IP network can have a gateway to communicate beyond the LAN that is identified by the network ID. A gateway is a computer or electronic device that is connected to two different networks and can move TCP/IP data from one network to the other. A single LAN that is not connected to other LANs requires a default gateway setting of 0.0.0.0. If you have a gateway, then the default gateway would be set to the appropriate value of your gateway.

> • | Ethernet Address: An Ethernet address (also known as a MAC address) is a unique 48-bit value that identifies a network interface card to the rest of the network. Every network card has a unique ethernet address permanently stored into its memory.

> 8‑pin Ethernet RJ45 Connector Pinout Diagram
> Pin | Name | Description | Wire Color
> 1 | TX + | Transmit data (> + 3 volts) | White/Orange
> 2 | TX – | Transmit data (< – 3 volts) | Orange
> 3 | RX + | Receive data (> + 3 volts) | White/Green
> 4 | — | Not used (common mode termination) | Blue
> 5 | — | Not used (common mode termination) | White/Blue
> 6 | RX – | Receive data (< – 3 volts) | Green
> 7 | — | Not used (common mode termination) | White/Brown
> 8 | — | Not used (common mode termination) | Brown

> Connectivity
> TCP/IP connectivity requires setting up the parameters that are described at the beginning of this section. The following is a brief overview of how to set up a general LAN connection on the Site Master.

> Note | You may need to consult your network documentation or network administrator for assistance in configuring your network setup.

> Site Master LAN Connections
> The S331L requires the use of an external USB-Ethernet dongle, such as Anritsu part number 2000‑1810‑R, to connect the Site Master to a local area network (LAN). Integrated into this dongle are two LEDs (Light Emitting Diodes). The amber LED indicates the speed of the LAN connection (ON for 100 Mb/s and OFF for 10 Mb/s), and the green LED flashes to show that LAN traffic is present. The instrument IP address is set automatically by using Dynamic Host Configuration Protocol (DHCP). DHCP is an Internet protocol that automates the process of setting IP addresses for devices that use TCP/IP, and is the most common method of configuring a device for network use. After the Ethernet cable is connected to the instrument, go to System, Status, Connectivity Info to view the IP address that the instrument has been assigned.