System Enhancement Module (SEM) for VISTA w/ Verizon LTE Cat-M1 and IP Communicator

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The ADC-SEM300-VT-VZ-M is a System Enhancement Module (SEM) that allows a Honeywell VISTA alarm system to utilize the ecosystem. Purchase the ADC-SEM300-VT-VZ-M from Alarm Grid!
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The ADC-SEM300-VT-VZ-M is a System Enhancement Module (SEM) that allows a Honeywell VISTA alarm system to utilize the ecosystem. Traditionally, VISTA panels have only been compatible with AlarmNet communicators, giving them access only to the Total Connect 2.0 platform.

This is not the only SEM for VISTA panels that offers. There is another SEM for VISTA panels that is offered for use with the Verizon network. The ADC-SEM300-VT-VZ also uses the Verizon LTE network, but the difference is that the ADC-SEM300-VT-VZ-M uses the LTE Cat-M1 network. The Cat-M1 network was created specifically for use with IoT (Internet of Things) projects. Compared to traditional LTE communication, LTE Cat-M1 has an upload speed of about 200 - 400 Kilobits Per Second. This may seem very slow, but the packets of data being transmitted on behalf of an alarm system are small in comparison to those required for voice communication via cellular. So, though this technology may not be suitable for traditional voice communication, it works very well for alarm systems.

VISTA alarm systems are manufactured by Resideo, formerly Honeywell Security. This is also the parent company of AlarmNet. AlarmNet is the IP and Cellular communication platform behind Total Connect 2.0. This is why most VISTA systems are used with AlarmNet Communicators. They were literally made for each other. With the introduction of the SEM modules, has made using a VISTA system with's remote control services possible. Some customers prefer the flexibility and reliability of a VISTA alarm panel, which can support both wired and wireless contacts, but also prefer the interactive platform rather than the Total Connect 2.0 one. With the SEM, those customers can have the best of both worlds.

Verizon is known for its robust and reliable cellular network. In addition to cellular communication, the ADC-SEM300-VT-VZ-M also offers an Ethernet connection, allowing the user to take advantage of a wired internet connection that is likely already in place. Using both paths is called Dual-Path monitoring, and it is highly recommended. When an communicator has a dual path available, it sends all signals on both paths. Whichever signal reaches first is processed, and the signal that is received second is discarded. By always utilizing both paths, makes sure that all signals always arrive using the fastest available path.

For those who want to use Z-Wave devices in conjunction with their account, the ADC-SEM300-VT-VZ-M also functions as a Z-Wave Plus Controller. When the built-in Z-Wave controller is used, then Z-Wave devices can be controlled remotely via the platform, and rules and scenes can be programmed via the webpage and/or app. In this configuration, there will be no local control of Z-Wave devices except for via the app or webpage. If the user wishes to use a Honeywell Home Tuxedo Keypad with a Z-Wave controller built-in, they can, but by doing so they lose the ability to control Z-Wave devices remotely through

Due to its relatively low power consumption, the ADC-SEM300-VT-VZ-M doesn't require a separate power supply. Instead, it can receive its power directly from the VISTA alarm panel. It has a nominal (continuous) current draw of 125 mA with a maximum of 230 mA when transmitting. Be sure to include these figures into any current draw calculations for the panel when considering how peripherals are powered, as well as when calculating standby battery requirements.

This product is compatible with the VISTA-10P, VISTA-15P, VISTA-20P and VISTA-21iP panels manufactured in 2005 or later. The date of manufacture should be on the square chip near the center of the board. It has a white sticker on it. In order for the SEM to be compatible with the VISTA-21iP, the panel's internal communicator jumper must be set to OFF. This removes power from the internal communicator, freeing the panel to use an external one. Be sure when moving the jumper to the OFF position that you power the panel completely down first to avoid damaging the board. In order to take full advantage of the features offered by the ADC-SEM300-VT-VZ-M, including the ability to program the panel remotely via, the panel version must support Compass IP Downloading. For the VISTA-10P, this is version 2.0+. For the VISTA-15P and VISTA-20P, this is version 5.2+, and for the VISTA-21iP, this is version 3.1+.

If you need an AT&T version of the SEM, check out the ADC SEM300-VT-AT-M.

Compatibility Notes:
  • The SEM is compatible with Touchscreen Keypads. Arming, Disarming, Panics and Alarms initiated through these keypads are processed through However, changes to the Installer Code via Quick Programming Mode and bypassing of open sensors through the touchscreen will not be processed by unless they are performed using Console Mode.
  • To use the "Bypass Open Sensors" feature in, panel programming field *23 Forced Bypass must be enabled, and is not enabled by default.
  • The AVS (Audio Verification System) is incompatible with the SEM. If the panel is using an AVS system, it must be removed in order for the SEM to function properly.
  • The 4232CBM (Connected Building Module) is not compatible with the SEM.
  • Plain Old Telephone Service (POTS) is incompatible with the SEM. When a SEM is being used, it should be the only communication path for alarm signaling.
  • SAM (Sensor Activity Monitoring) is not available for the 5822T Tilt Sensor. Be sure SAM is disabled for any of these sensors.


  • Power Requirements: 12V Nominal, 125 mA Continuous, 230 mA Max
  • Cellular Network: 4G LTE CAT-M1 Network, No Fallback
  • Panel Interfaces: Two Keypad Bus Connections (Data In, Data Out) 12V Power and Ground
  • Enclosure Indicators: Five (5) LEDs (Red, Green, Yellow, or Blue)
  • Operating Temperature: 14℉ - 131℉ (-10℃ - +55℃)
  • Storage Temperature: -30℉ - 140℉ (-34.4℃ - +60℃)
  • Humidity: 90% Relative Humidity, Non-Condensing
  • Enclosure Dimensions: 7.66"L x 4.35"W x 1.65"D (19.46cm x 11.05cm x 4.19cm)
  • Enclosure Color/Material: White Fire-retardant PC/ABS, PC

Brand: Honeywell Honeywell Home Resideo ADC-SEM300-VT-VZ-M Compatible Products

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