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Damocles2 1208: Secure I/O over Ethernet

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Damocles2 1208 provides 12 digital inputs and 8 digital outputs over the Ethernet and a secure Web interface. Secure communication supports connection to SNMP v3, SCADA systems and MQTT portals for IoT. Pulse counters on digital inputs.

Damocles2 1208 is an Ethernet I/O unit with enhanced security and an excellent cost per I/O pin ratio. Inputs and outputs can be controlled over the secure Web interface or various M2M protocols.

Digital inputs can be used to connect up to 12 dry contacts (e.g. door contacts) or S0 pulse outputs (e.g. electricity meter).
Digital outputs (open collector) can be used to control relays, or for example switch 110/230V sockets (via PowerEgg2).

Damocles2 1208 fits on a DIN rail. Outputs are OC (Open Collector), can control external relays but are not electrically isolated.

E-mail and SMS alerts

When the state (open/closed) of a contact connected to a digital input changes, Damocles2 can send an e-mail to a maximum of 5 recipients (or a SNMP Trap / SMS alert).

Dry contact alarm can be delayed (for example to send an alert if a cooler door stays open for more than 5 minutes). Damocles2 can send e-mail using the secure TLS protocol.

All HW group devices can send text messages (SMS) through a single central gateway, the HWg-SMS-GW. Just a single SIM card can serve all your devices.

Remote digital outputs (Box-2-Box mode)

Digital outputs (DO) of Damocles2 1208 can be controlled over a LAN from other HW group products. We call this the “Box-2-Box” mode. For example, alarms from several Poseidon2 units or water leak detectors can be signaled at a single location with a single Damocles2 1208 unit.

Secure signaling of I/O states over a LAN

Damocles2 supports secure protocols for M2M communication with central software.

  • SNMP v3
  • MQTT for cloud (IoT) applications
  • XML over HTTPs
  • TLS for sending e-mail


A typical application of Damocles2 1208 is secure connection of remote DI (digital inputs) and DO (digital outputs) to a software. Customers use it to monitor doors in a building, security system status, or various detectors. It can be connected to over 50 different third-party SNMP or SCADA applications.

Some customers use Damocles2 and its S0 counter function in smart homes to monitor the technology and for water or electricity consumption billing (with a S0 energy meter).

Damocles2 1208: Secure I/O over Ethernet


Damocles2 1208 main photo    Sides view    Bottom view

  Set package    Damocles2 1208 top view 

HWg-SMS-GW for sending SMS


  • Ethernet: RJ45 (10/100 BASE-T)
  • WEB: Built-in web server (IPv6, HTTP, HTTPs)
  • Data logger: Data logger for more than 250.000 records
  • Digital outputs (DO): 8 digital outputs, OC (open collector) type  
  • Digital inputs (DI): 12x dry contact input (for state detectors)
    Supports: Door contacts, smoke detectors, 110/230V power supply detector, water leak detector, fan failure detector, electricity meter with a S0 output, water meter with a S0 output.
  • Pulse counters: 32-bit S0 counter at every dry contact digital input (DI)

  • Power supply: 9-30V DC
  • Operating temperature: -30°C to +65°C (14°F to +140°F)
  • Mechanical: Plastic box, wall-mountable, DIN rail, 145 x 90 x 40 [mm] (H x W x D)
  • Warranty: 2 years
  • Cloud support: HWg-Push protocol, MQTT
  • Reaction to a change at a DI (dry contact): SNMP trap, Email (TLS), SMS
  • Sending text messages (SMS) and dialing numbers: Alerts can be sent as text messages (SMS) via a remote “HWg-SMS-GW3” over the network, to a maximum of 5 phone numbers.
  • I/O over EthernetM2M communication protocols: SNMP (SNMP version 1 and version 3), XML (HTTPs), Modbus/TCP, MQTT, HWg-Push
  • Box-2-Box mode: DO of Damocles2 can be used as outputs by other HW group products on the same LAN.
  • Support for programmers: HWg-SDK
  • Recommended online portal: – free online portal
  • Supported software
    • HWg-Trigger: Control of other IP devices, alarm redirection to SMS
    • HWg PDMS: Logging, export to MS Excel, reports
    • Third-party software (SCADA systems, Modbus/TCP)


Damocles2 product family

  Damocles2 MINI
Damocles2 1208

Damocles2 2404
LAN Interface
DO (Digital Outputs) 2
(Open Collector)
DI (Digital Inputs) 4 12 24
32bit pulse counter on each DI
HWg-SMS-GW support
HWg-Push protocol (required for
SNMP v3 & HTTPs secure protocols
-48V power for Telco
VDO (Virtual Digital Output)
PoE (IEEE 802.3af) support

Usage examples

    Damocles2 1208 is Ethernet open collector, digital output, modbus tcp, web io,
  • Central indication of equipment status
    Damocles2 1208 signals alarm states from several Poseidon2 or WLD units dispersed around a building (VDO – Virtual Digital Output). 
  • Energy consumption metering
    Counting of pulses from S0 outputs of electricity / water / gas meters.
    Conversion to price per time period using HWg-PDMS and MS Excel.
  • Interface for connecting I/O to the Ethernet (high security web IO)
  • Connecting I/O to a cloud portal (MQTT protocol)
  • Remote monitoring of dry contact inputs:
    monitoring of various legacy technologies over IP
  • Smart buildings: States of inputs and outputs can be shared in several different applications. Secure communication over IP (HTTPs / SSL security).

Remote I/O monitoring

Remote I/O monitoring – machinery monitoring
  • Damocles2 1208 can be used to remotely monitor various machinery and detect alarm situations.
  • Damocles2 supports industry-standard Modbus/TCP protocols to connect to SCADA systems.
  • Damocles2 1208 can be easily connected to a cloud using the MQTT protocol.
  • High security of network communication is ensured by using HTTPs/SSL or SNMPv3.
  • Values are logged, the log can be displayed and processed e.g. in the HWg-PDMS utility for Windows.


Secure connection of I/O over Ethernet

Secure connection of I/O over Ethernet  - ipv6, snmpv3, network io, ethernet io module, IP I/O, IO remote, network I/O control, ethernet relay controller
  • Damocles2 monitors the status of security systems and connects to camera surveillance systems.
  • Alarms from individual zones are connected as dry contacts to digital inputs.
  • Open collector outputs of Damocles2 1208 can be easily connected to a security system or smart home control.
  • DI and DO states can be easily connected to a SCADA system, a BMS (Building Management System), etc.
  • One Damocles2 unit can be connected to multiple systems at the same time.
  • For secure applications, IPv6 or SSL communication over XML (HTTPs) and SNMPv3 can be used.

Detectors (most popular)

FDR26 Smoke Detector

Smoke detector (12VDC power, relay output)

Door Contact

Open door detector

Impaq shock sensor

Vibration detector (12VDC power, relay output)

Gas Leak Detector

Detector of flammable gases (12V, relay output)


Power failure detector (relay output)

Motion PIR detector

Motion detector (12VDC power supply)

>> Overview of all sensors and detectors

Software and applications

>> Software and applications

Damocles2 1208 – Open Collector outputs

Electrical connection of the OC outputs has been changed in the second generation Damocles2 products compared to the previous Damocles generation.

open collector, digital output, modbus tcp, web io, Damocles 1208 (first generation):

  • In the first generation of Damocles 1208, the common pin of protection diodes was available, and a relay coil could be connected to each DO (OC type) without the need for an external protection diode.
  • It was more complicated to connect to digital inputs of other devices.

Damocles2 1208

Connecting to the online portal

  • Damocles2 1208 can be connected to the online portal.
  • From the SensDesk portal, the remote relay outputs can be controlled.
  • All devices, digital inputs (DI), relay outputs, history and charts can be viewed from anywhere over the web, or in a mobile app.
  • For programmers: Devices connected to the portal can be monitored using a XML interface.
  • Cloud sensor: Damocles2 can be connected to cloud systems for IoT (MQTT).

security, ipv6, snmpv3, DIN rail, dry contact, digital input, dry contact input, snmp relay, modbus tcp, s0 counter, remote power off, remote shutdown, remote control switch,  network io, ethernet io module, IP I/O, IO remote

>> About online portal

Text message (SMS) alerts

SMS alerts can be sent from the Damocles2 1208 monitoring unit in several ways:

Text message (SMS) alerts

  • Directly over the network using SMS-GW
    A text message can be sent from the Damocles2 I/O unit to a specified phone number using the HWg-SMS-GW gateway.
    No software is needed. HWg-SMS-GW should be connected to the same LAN. Sender's phone number is defined by the SIM inserted in the HWg-SMS-GW unit. Recipient's phone number is configured in the Damocles2 unit, similarly to e-mail recipients.
    One HWg-SMS-GW gateway can be shared by several devices (e.g. the STE2 WiFi/LAN thermometer in the picture).
  • With the HWg-Trigger application for Windows
    The HWg-Trigger application can run in the background on any PC with MS Windows. The application checks for device failures, disconnected sensors, or sensor readings outside of the Safe Range. Alarm status can be notified e.g. by sending a SMS to a specified number using a “HWg-SMS-GW” in the same LAN.
  • With third-party software applications
    Many SCADA (e.g. CapTemp) or SNMP (Nagios, Zabbix, ..) applications can monitor the status of the Damocles2 unit and send alerts via SMS.


Frequently Asked Questions

    Ask for the price or details:
     - Web:  http://
    Country: *

    Spam protection. How many is SIX times six?

  • What is the difference between Damocles2 and Poseidon2?
    – Poseidon2 reads values from various sensors and only features a few I/O inputs and outputs.
    – Damocles2 only supports I/O (inputs/outputs), does not support any sensors. Damocles2 features a pulse counter at each input. Only a Damocles unit can work as the output for the Box-2-Box mode based on SNMP traps and input/sensor names.
  • Damocles2 1208 has open collector outputs instead of relay outputs. What does that mean?
    Instead of output relays, Damocles2 model 1028 uses transistors in a circuit called OC (Open Collector). Digital outputs (DO) are NOT electrically isolated, and it is necessary to pay attention to polarity when connecting to digital inputs (DI).
    For details, see the manual or contact our technical support.
  • Can I control the remote IO (digital outputs) using the Damocles2 web page?
    Yes. However, the output must be in the "Manual" mode.
    If the output is in the "Local condition" mode, change its mode to "Manual" first.
  • I found several different Damocles2 devices. Are there any differences in their functions?
    Different Damocles2 models differ by the number of digital inputs and outputs, power options (12V / PoE / -48V) and the type of outputs (relay / open collector).
    All Damocles2 models are the same in terms of protocols and software.
  • Is it possible to connect Damocles2 1208 to a cloud (IoT applications)?
    Yes, Damocles2 is a “cloud oriented device”. It can be connected to cloud systems as a “Cloud sensor”.
    Use the HTTP-based HWg-Push protocol, MQTT, or contact us for details.
  • Can Damocles2 1208 measure energy consumption?
    Yes. However, you need an external meter with a pulse output (S0). S0 pulses can then be counted at a digital input (DI) of the Damocles2. To measure energy consumed over a time period, e.g. [kWh] or [J], we recommend to use the HWg-PWR 3/12/25 device and a M-Bus enabled electricity meter, gas meter, water meter or heat meter.
  • Damocles2 1208 web i/o supports pulse counting at digital inputs. What happens if the device is restarted?
    Damocles2 features a non-volatile memory that keeps the counter state even if the power supply is interrupted.
    The 32-bit counter (max value: 4294967296) can be only reset over the web interface.
  • Can Damocles2 log values?
    Yes, Damocles2 includes an internal memory for the data logger. Data are kept even if the power goes off. The logger has a capacity for 250,000 records.
  • Damocles2 supports HTTPs. Can I upload my own certificate to the device?
    Yes, a security certificate can be uploaded to Damocles2. For details, see AN46: HTTPS in Poseidon2 and Damocles2 units.
  • Do you offer a SW solution that will alert me to a failure of a Damocles2 unit?
    Yes, you can use the HWg-Trigger application that runs on any Windows PC.
    Another option is the online service – a portal for HW group devices.
  • Can I control digital outputs of Damocles2 from the SensDesk portal?
    Yes. However, depending on the configuration, the action can be delayed by up to several minutes.

  • What is the maximum number of e-mail recipients for alerts?
    Damocles2 itself can send e-mails to at most 5 e-mail addresses.
    With the online service or the HWg-Trigger application for Windows, e-mail alerts to OK/Alarm states can be sent to more than 5 e-mail addresses.
  • Is there an app for my mobile phone?
    Yes, several third-party apps for Android and Apple are available here: Android and iPhone mobile app for HW group products
  • Can Damocles2 1208 detect the presence of 230VAC (e.g. the input voltage of an UPS)?
    Yes, use the input voltage detection feature of a PowerEgg unit, or any relay with a contact connected to one of the IN1-IN4 “Dry Contact” inputs. Digital Output of a Damocles2 1208 can control a 110/230V output of a PowerEgg (pay attention to the polarity, GND must be connected to the GND pin).
  • Can I connect voltage detection to DI (“wet contact”)?
    No, digital inputs (DI) are designed for direct connection of a voltage-free contact (“dry contact”), such as a door contact or a relay output.
  • What is the warranty?
    The standard warranty is 2 years, can be extended upon request.
  • Where can I find the prices of your devices?
    Ask our distributors, or request a quote from us (by e-mail or by filling out this form).

>> Online order form



Product Description
Damocles2 1208 set Damocles2 1208 quick start set with a power adapter.
Contains a Damocles2 1208, a universal power adapter, a CD and a manual. - photo
Damocles2 1208 Damocles2 1208 stand-alone device.
A Damocles2 unit without accessories. - photo
HWg-SMS-GW3 Central SMS Gateway – start set
Central GSM SMS gateway for sending text messages from other HW group devices over the LAN. Includes an internal GSM modem, an external antenna with 3m cable, a power adapter and a CD. - photo



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