MILESTONE ELECTRONICS
8 Contact Closure to 1 Serial Out
The ML-8CCS converts 8 independent contact closure inputs into RS232 serial output data. Each contact closure event generates a defined ASCII command transmitted over a standard D9 female RS232 port, enabling reliable integration with serial-controlled systems and automation equipment.
- Converts 8 contact closure channels into RS232 serial output via a single D9 female port
- Each channel connected via 4-pin captive screw terminals, with 2 channels per connector block
- Toggle switch enables dual function operation on a single contact closure channel
- LED indication provided for power status and RS232 output activity
- Communication parameters: 9600 baud, 8-bit data, 1 stop bit, no parity
Yes
Max Resolution
1080p Full HD
Audio Input
Stereo Analogue
Output
Single HDMI
- In-house manufactured
- 24hr response
- 2,000+ clients served
Product Overview
What the ML-8CCS delivers
The ML-8CCS is a contact closure to RS232 converter that accepts 8 independent contact closure inputs and outputs corresponding RS232 serial data through a single D9 female connector. It is designed for use in control systems, automation setups, and AV installations where physical switch closures or relay outputs from external equipment need to be interpreted as serial commands.
Each of the 8 contact closure channels is connected via 4-pin captive screw terminals, with each terminal block serving 2 channels. When a contact is closed, the device transmits a predefined ASCII character followed by an exclamation mark over the RS232 output. Channels 1 through 8 transmit single-character commands in sequence, using both numeric and lowercase alphabetic characters as defined in the command table.
A toggle switch at the rear of the unit enables dual-function operation per channel. With the toggle switch ON, operating a contact closure for the first time sends one command, and a second operation on the same channel sends an alternate command. This allows a single physical input to trigger two distinct serial outputs, effectively doubling the number of controllable states without adding hardware.
The unit includes LED indicators for power status and RS232 output activity, providing at-a-glance confirmation of device operation and signal transmission. The RS232 output pin assignment uses Pin 3 for Rx and Pin 5 for ground on the D9 female connector. All communication operates at 9600 baud, 8-bit data, 1 stop bit, and no parity.
Contact Inputs
Input Connectors
RS232 Output
Baud Rate
Data Format
Toggle Switch
Yes
Mains Input
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Key Features
8-channel contact closure conversion to serial output
Plug-and-play conversion of contact closure signals to RS232 data, with LED status indication, toggle switch dual-function support, and captive screw connectivity.
8 Independent Contact Closure Inputs
The ML-8CCS supports 8 separate contact closure channels, each capable of triggering a unique RS232 command output. Every channel is electrically independent, allowing simultaneous or sequential closure inputs from external control devices, relays, or switches without cross-channel interference.
- 8 channels available for discrete contact closure signals
- Each channel produces a unique ASCII command on RS232 output
- Suitable for relay outputs, push buttons, and dry-contact switches
4-Pin Captive Screw Terminal Inputs
Contact closure channels are connected through 4-pin captive screw terminals, with each terminal block accommodating 2 channels. The captive screw design ensures secure and vibration-resistant connections without the need for proprietary connectors, simplifying field wiring in fixed installations.
- 4 terminal blocks, each supporting 2 contact closure channels
- Captive screw design ensures secure field termination
- No proprietary connectors required for wiring
Toggle Switch for Dual-Function Operation
A rear-panel toggle switch enables dual-function mode per channel. When this switch is ON, the first contact closure on a given channel transmits one command, and the second closure on the same channel transmits an alternate command. This feature doubles the number of distinct outputs achievable without requiring additional hardware inputs.
- Single channel can produce two distinct RS232 commands alternately
- Toggle switch located on the rear panel for controlled configuration
- Useful for toggle-type control functions such as power on and power off
LED Indication for Power and RS232 Output
Dedicated LED indicators are provided for power status and RS232 output activity. The power LED confirms the unit is receiving mains supply, while the RS232 output LED provides visual confirmation each time a serial command is transmitted. This simplifies fault-finding and commissioning in the field.
- Separate LEDs for power and RS232 output status
- RS232 LED confirms each command transmission event
- Supports quick visual verification during installation and testing
RS232 Output via D9 Female Connector
Serial data is output through a standard D9 female connector on the rear panel. The RS232 output uses Pin 3 for Rx and Pin 5 for ground, conforming to standard RS232 wiring. Communication operates at 9600 baud, 8-bit data, 1 stop bit, and no parity, ensuring compatibility with a wide range of serial-controlled devices and control systems.
- D9 female RS232 output on rear panel
- Pin 3 (Rx) and Pin 5 (GND) as per standard RS232 pinout
- Fixed parameters: 9600 baud, 8N1
Plug and Play Installation
The ML-8CCS is designed for straightforward installation with no complex configuration required. Connect the contact closure inputs via the captive screw terminals, connect the RS232 output to the target serial device, and power the unit from 230V AC mains. The device begins operating immediately upon power-up with no software setup or driver installation needed.
- No software configuration or drivers required
- Operational immediately upon connecting inputs and applying power
- Suitable for fixed installations in control rooms and AV setups
Installation
Connecting contact closures to RS232 output
The ML-8CCS connects directly between dry-contact or relay output sources and any RS232-controlled device. Installation involves terminating the contact closure inputs, connecting the RS232 output, and configuring the toggle switch as required.
01
Contact Closure Input Wiring
Each pair of contact closure channels is connected to one 4-pin captive screw terminal block on the unit. Channels are wired using the contact and common (C) signal points: pins labeled 1 and C correspond to Channel 1, and pins labeled 2 and C correspond to Channel 2. This pattern repeats across all 4 terminal blocks to cover all 8 channels. Standard field wiring is used and no specialised cable is required.
02
RS232 Output Connection and Toggle Configuration
Connect the D9 female RS232 output port on the rear panel to the serial input of the target device using a standard RS232 cable. Pin 3 carries the Rx signal and Pin 5 carries ground. Set the communication parameters of the receiving device to 9600 baud, 8-bit data, 1 stop bit, and no parity. If dual-function operation is required on any channel, set the rear-panel toggle switch to the ON position before powering up. Once powered from 230V AC mains, the unit begins transmitting ASCII commands on every contact closure event.
Where the ML-8CCS performs
Suited for any environment where physical switch closures, relay outputs, or sensor triggers need to be translated into RS232 serial commands for downstream control systems.
AV Control Room Integration
Use physical push buttons or relay outputs to send predefined serial commands to AV controllers, matrix switchers, or presentation systems. Each button press closes a contact and triggers a corresponding RS232 command without requiring a dedicated control processor.
Building Automation Systems
Interface dry-contact outputs from building management or access control systems with serial-controlled equipment. The ML-8CCS bridges the gap between traditional relay-based infrastructure and modern RS232-enabled devices, enabling event-driven serial command dispatch.
Boardroom and Presentation Setups
Map physical control panel buttons to RS232 commands for displays, projectors, or video switchers. The toggle switch feature allows a single button to alternate between two commands, such as input source selection, without adding extra hardware.
Security and Access Control
Convert door sensor closures, motion detector outputs, or alarm relay contacts into serial data for logging or triggering control actions on connected serial devices. The 8-channel capacity accommodates multiple zones within a single installation.
Educational Institutions
Allow teachers to operate serial-controlled display or AV equipment from simple push-button panels installed at lecterns or podiums. The plug-and-play design requires no programming expertise and can be installed and commissioned quickly in classroom or lecture hall environments.
Industrial and Process Control
Accept relay or limit switch outputs from industrial equipment and transmit serial commands to SCADA terminals, HMI units, or serial-controlled actuators. The captive screw terminals support robust field wiring suitable for industrial panel installation.
Full specification sheet
- Model Information
- Input
4
- RS232 Output
Rx
Ground
1
None
- Command Output
- Controls and Indicators
- Power
FAQs about the ML-8CCS
What does the ML-8CCS convert and what is it used for?
The ML-8CCS is a contact closure to RS232 converter. It accepts up to 8 independent contact closure inputs, such as relay outputs, push buttons, or dry-contact sensors, and converts each closure event into a corresponding ASCII serial command transmitted over a single RS232 output port. It is used in AV control, building automation, and industrial applications where physical switch states need to be relayed as serial data to downstream equipment.
What commands does the ML-8CCS send when a contact is closed?
Each channel sends a fixed ASCII command followed by an exclamation mark. Channel 1 sends 1!, Channel 2 sends 2!, through to Channel 8 which sends 8!. These commands are transmitted as ASCII characters over the RS232 output. When the toggle switch is enabled, the first and second closures on the same channel alternate between two distinct commands, for example, Channel 1 sends 1! on the first press and A! on the second press.
What are the RS232 communication parameters required at the receiving device?
The receiving serial device must be configured to match the ML-8CCS output parameters: 9600 baud rate, 8 data bits, 1 stop bit, and no parity. These parameters are fixed on the ML-8CCS and cannot be changed. Ensure the target device is set to these values before connecting the RS232 output to avoid communication errors.
How does the toggle switch work and when should it be used?
The toggle switch is located on the rear panel of the ML-8CCS. When set to ON, it enables dual-function operation across all channels. In this mode, the first contact closure on a channel transmits the standard single-contact command, and the next closure on the same channel transmits a different alternate command. For example, Channel 1 will alternately send 1! and A! on successive presses. This feature is useful when a single physical button needs to control two different states, such as turning a device on and then off, without requiring two separate input channels.
How are the contact closure inputs physically connected to the ML-8CCS?
Contact closures are connected via 4-pin captive screw terminal blocks on the unit. Each terminal block accommodates 2 channels. Within each block, pins labeled 1 and C form the contact pair for Channel 1, and pins labeled 2 and C form the contact pair for Channel 2. This arrangement continues across all 4 terminal blocks to cover all 8 channels. Standard field wiring is used and the captive screw design holds conductors firmly in place without requiring crimped terminations or specialist tooling.
Can the ML-8CCS be used with a PC or only with dedicated RS232 control systems?
The ML-8CCS outputs standard RS232 serial data through a D9 female connector and is compatible with any device that accepts RS232 input at 9600 baud, 8N1. This includes dedicated AV controllers, automation processors, SCADA terminals, and personal computers equipped with a serial port or USB-to-serial adapter. The device receiving the commands must be configured to accept the specific ASCII command strings generated by the ML-8CCS and act on them as required by the application.
What other models are available if more or fewer contact closure channels are needed?
Milestone Electronics manufactures the same converter in four channel configurations. The ML-4CCS supports 4 contact closure inputs, the ML-8CCS supports 8, the ML-12CCS supports 12, and the ML-16CCS supports 16. All models share the same RS232 output interface, LED indication, and toggle switch feature. The appropriate model should be selected based on the number of independent contact closure inputs required in the installation.
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