Daisy Chaining Device Servers Via Ethernet
A device server intended for attaching serial devices to a network includes Ethernet communications, an Ethernet switch, and serial communication capability so that multiple device servers are connected in a “daisy chain” or series pattern. Galvanic isolation of the power supply from the housing and communication ports, screw terminal and modular connections, DIN rail mounting, broad power supply voltage ranges or “Power-over-Ethernet” and operator visible indicator lamps with a pulse stretching feature greatly simplify installation and use.
1 . A device comprising:
a first plurality of communication ports configured to adhere to a first communication standard;
a second plurality of communication ports configured to adhere to a second, different communication standard; and
circuit board coupled with the first and the second plurality of communication ports and including a switch configured to provide a daisy chained capability among the first plurality of communication ports as well as among second plurality of communication ports.
2 . The device of claim 1 , further comprising wherein the first plurality of communication ports include serial ports that adhere to a second serial communications port coupled to the circuit board. communication standard as the first communication standard.
3 . The device 2 , wherein the serial communication standard includes at least one of the following: RS-232, RS-422, and RS-485.
4 . The device server of claim 1 , wherein the second plurality of communication ports include Ethernet ports.
5 . The device wherein the Ethernet ports comprises a wireless Ethernet port.
6 . The device of claim 1 , wherein the switch comprises an Ethernet switch.
7 . The device of claim 1 , wherein the switch comprises a microprocessor configured to execute software instructions stored in a memory and that cause the microprocessor to implement switch functionality.
8 . The device of claim 1 , further comprising a memory storing a port address table.
9 . The device of claim 8 , wherein the switch is configured to route packets among the first and the second plurality of communication ports according to the port address table.
10 . The device of claim 1 , wherein the switch is configured to route packets not intended for the device to other daisy chained devices coupled with the device via at least one of the first and the second plurality of communication ports.
11 . The device of claim 10 , wherein the switch is configured to route packets among the other daisy chained devices according to a packet switching protocol.
12 . The device of claim 11 , wherein the packet switching protocol comprises a spanning tree protocol.
13 . The device of claim 1 , further comprising a housing in which is disposed the circuit board.
14 . The device of claim 13 , further comprising a of DIN rail attachment feature.
15 . The device of claim 1 , wherein the first plurality of communication ports comprise screw terminal connections.
16 . The device of claim 1 , wherein the second plurality of communications ports includes a power over Ethernet connection configured to supply power to the circuit board.
17 . The device of claim 1 , further comprising a protocol converter configured to convert packets from the first communication standard to the second communication standard.
18 . The device of claim 17 , wherein the protocol converter is further configured to convert packets from the second communication standard to the first communication standard.
19 . The device of claim 17 , wherein the protocol converter comprises a serial to Ethernet converter.
20 . The device server of claim 1 wherein the Ethernet switch function is operationally substantially equivalent to an Ethernet router function.
21 . A Serial to Ethernet Converter having a plurality of serial ports wherein at least two serial ports are logically connected in that information arriving at a first port is passed internally through the device server to a second port, and information arriving at the second port is passed internally through the device server to the first port.