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ED212 Ethernet Time Display
Now available with Power over Ethernet (PoE)

ED212 six digit ethernet time display

Theory of Operation
Network Interface
Power over Ethernet (PoE)
Serial Port
Relay Output
Power Supply
Software Interface
Physical Specifications


Tthe ED212 is a six-digit, high visibility (4" high digits), time of day Ethernet wall clock. The ED212's Ethernet connection allows its internal time-of-day clock to be periodically synchronized with a host computer clock over the network. (See the ED210 for a four-digit model.)

Time can be displayed in either standard military (00:00 - 23:59) format or in AM/PM (12:00AM - 11:59PM) format. Alarms can be set to trigger either the internal bell or an optional relay. The network interface supports both 10BaseT and 100BaseT Ethernet connections. Optional 802.11b/g wireless connectivity is also available.

Some of the uses for the ED212:

  • SNTP wall clock
  • SNTP time display
  • SNTP digital time display
  • TCP/IP wall clock
  • TCP/IP time display
  • TCP/IP digital time display
  • Ethernet wall clock
  • Ethernet time display
  • Ethernet digital time display

Theory of Operation

The ED212 can be used to display the current time, the timer value, or a message string. Selection of the display mode is dynamic and can be controlled through the network interface. A standard Telnet client or special application program can be used to control & configure the time display device.

As an employee time display, it can be synchronized to a master system clock via the network. Normally, a host computer on the network is designated as the master clock and will periodically update the time and date on all of the employee time clock (EC305) devices. The ED212 time display can be updated at the same time creating a completely synchronized timing system. A utility program (ET200UP) is provided with the ED212 that can be used to perform the update. If the host computer has internet access the system clock can also be synchronized with the NIST atomic clock.


The ED212 can be programmed to trigger an alarm at a certain time of day. Up to 32 alarms can be set and each alarm will either activate the internal bell or one of the 4 optional relay outputs. Alarms that trigger a relay output can be used to activate exter-nal bells, lights, counters, etc. The length of time that a relay is active can also be set by the alarm.

Network Interface

The ED212 connects to a 10BaseT or 100BaseT hub (or switch) via a standard RJ-45 Ethernet (CAT 5) cable. From a network perspective it occupies a single "socket" at a specified TCP/IP address and port number. The device must be configured with a unique IP address, net mask, and port number BEFORE it is installed on the network (see "Net-work Configuration"). The host software communi-cates with the ED210 by establishing a connection with it and then sending and receiving ASCII text command strings (see Software Interface).

Power over Ethernet

Optional Power over Ethernet (PoE) capacity is now available.


The ED212 has a six (6) digit, seven (7) segment LED display which displays the time in HH:MM format. Each of the red digits is 4" high and can be viewed from a distance of 100 feet. In the upper left corner is a dot use as a PM indicator used when the time is displayed in the Am/Pm mode. When ED212 is first powered on all display segments will be lit for about 2 seconds to verify their operation.

Serial Port

The serial RS-232 port is used to initially configure the ED212 via the "Aux Command Mode" which provides local communications with a terminal or computer. Access to the serial port is provided by a DB9M connector configured as a DTE device.

Relay Output

The ED212 can be equipped with four (4) solid state relay (SSR) outputs that can be individually activated as an alarm output. Each relay has a single "form A" contact rated at 10va (100vdc, 100ma.) maximum. If larger loads must be controlled use of an external relay is required. The relay outputs can be optionally configured to directly activate an external 12Vdc relay. For more information on external connections see application note AN0202 (pdf).

Power Supply

The ED212 is powered by a 12Vdc power adapter that plugs directly into a 120vac receptacle. Typical power consumption is less than 12 watts. Alternate power supplies are available for international customers or the ED212 can be powered using a 12Vdc supply connected to the power jack.

Mounting Bracket

The ED212 includes a bracket on the back side which allows the time display to be mounted on a vertical surface. Two (2) key hole slots in the bracket can be used to hang the ED212 with screws on a vertical surface. The bracket can be inverted or removed as desired.

Software Interface

Software communications with the ED212 is simple and straight forward. The primary TCP/IP port is used for communications with the user application program. Normally, the host software (client) is responsible for establishing a network connection with the ED212 (server) on a specified port. Alternately, the ED212 can be configured to automatically establish a connec-tion (client) with a host computer application (server) using the SERVER parameter.

Once the connection is established the host applica-tion software can set the time & date or other com-mands to the ED212. Typically, the data transfer is accomplished in ASCII character strings to minimize network packet traffic. The communications protocol is determined by the emulation mode and can be changed dynamically by the host software.

Physical Specifications

Large 4", 7 segment
10/100BaseT Ethernet (RJ-45)
Serial Port
Input/Output (RS-232)
Optional Relay control outputs (2 or 4)
23.5"W x 6.9"H x 3.3"D
6.8 Lbs.
Power Consumption -
Standard Unit: 15 Watts (max)
Temperature Ranges:
Operating: 0ºC to 60ºC (32ºF to 140ºF)
Storage Temperature: -30ºC to 70ºC (-20ºF to 158ºF)
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