Industrial Managed Gigabit Ethernet Switch (4-Port RJ-45, 4-Port Combo RJ-45/SFP)
User Manual for the LEH2004A-4GSFP (Version 1)
Hardened Managed Ethernet Switch User Manual
User Manual for the LEH900 Series, LEH1000 Series, LEH1100, & LEH1200 Series (Version 3)
- Visio Stencil Drawing...
- Quick Start Guide...
Industrial Managed Gigabit Ethernet PoE+ Switch (4-Port RJ-45, 2-Port SFP) QSG
Quick Start Guide for the LPH2004A-2GSFP (Version 1)
Product Data Sheets (pdf)...Industrial Managed Gigabit Ethernet Switches
- Quick Start Guide...
Industrial Managed Gigabit Ethernet Switch (4-Port RJ-45, 4-Port Combo RJ-45/SFP) QSG
Quick Start Guide for the LEH2004A-4GSFP (Version 1)
Hardened Gigabit Edge Switch (8-Port) User Manual
User Manual for the LGH008A (Version 1)
Black Box Explains...PoE phantom power.
10BASE-T and 100BASE-TX Ethernet use only two pairs of wire in 4-pair CAT5/CAT5e/CAT6 cable, leaving the other two pairs free to transmit power for Power over Ethernet (PoE) applications. However,... more/see it nowGigabit Ethernet or 1000BASE-T uses all four pairs of wires, leaving no pairs free for power. So how can PoE work over Gigabit Ethernet?
The answer is through the use of phantom power—power sent over the same wire pairs used for data. When the same pair is used for both power and data, the power and data transmissions don’t interfere with each other. Because electricity and data function at opposite ends of the frequency spectrum, they can travel over the same cable. Electricity has a low frequency of 60 Hz or less, and data transmissions have frequencies that can range from 10 million to 100 million Hz.
10- and 100-Mbps PoE may also use phantom power. The 802.3af PoE standard for use with 10BASE-T and 100BASE-TX defines two methods of power transmission. In one method, called Alternative A, power and data are sent over the same pair. In the other method, called Alternative B, two wire pairs are used to transmit data, and the remaining two pairs are used for power. That there are two different PoE power-transmission schemes isn’t obvious to the casual user because PoE Powered Devices (PDs) are made to accept power in either format.
The difference between unmanaged, managed, and Web-smart switches
With regard to management options, the three primary classes of switches are unmanaged, managed, and Web smart. Which you choose depends largely on the size of your network and how... more/see it nowmuch control you need over that network.
Unmanaged switches are basic plug-and-play switches with no remote configuration, management, or monitoring options, although many can be locally monitored and configured via LED indicators and DIP switches. These inexpensive switches are typically used in small networks or to add temporary workgroups to larger networks.
Managed switches support Simple Network Management Protocol (SNMP) via embedded agents and have a command line interface (CLI) that can be accessed via serial console, Telnet, and Secure Shell. These switches can often be configured and managed as groups. More recent managed switches may also support a Web interface for management through a Web browser.
These high-end switches enable network managers to remotely access a wide range of capabilities including:
Enabling and disabling individual ports or port Auto MDI/MDI-X.
Port bandwidth and duplex control.
IP address management.
MAC address filtering.
Port mirroring to monitor network traffic.
Prioritization of ports for quality of service (QoS).
802.1X network access control.
Link aggregation or trunking.
Managed switches, with their extensive management capabilities, are at home in large enterprise networks where network administrators need to monitor and control a large number of network devices. Managed switches support redundancy protocols for increased network availability.
Web-smart switches—sometimes called smart switches or Web-managed switches—have become a popular option for mid-sized networks that require management. They offer access to switch management features such as port monitoring, link aggregation, and VPN through a simple Web interface via an embedded Web browser. What these switches generally do not have is SNMP management capabilities or a CLI. Web-smart switches must usually be managed individually rather than in groups.
Although the management features found in a Web-smart switch are less extensive than those found in a fully managed switch, these switches are becoming smarter with many now offering many of the features of a fully managed switch. Like managed switches, they also support redundancy protocols for increased network availability.
- Application Note...
LEH Series Ethernet Swtich Application Note
Network Redundancy with LEH Series Ethernet Switches (Version 1)