July 2022 Archives

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Power over Ethernet, also known as PoE allows power to be sent to a device using the same ethernet wire and RJ45 connector that is used for the network connection. Originally designed with VoIP phones in mind, PoE has quickly become a desirable option for IP cameras and other networked equipment.

Before we talk about PoE, we should discuss network cabling. Category 5 (Cat5), Category 5e (Cat5e), and Category 6 (Cat6) cables all consist of four (4) twisted pairs of wire, or a total of eight (8) conductors. The differences between these various categories of cable have to do with their ability to transfer data, over what distance, and at what speed. Generally, Cat6 is faster than Cat5 or Cat5e, and is less prone to crosstalk or noise issues.

The main point we want to make about network cabling, though, is this: With eight (8) conductors, any device that connects to a network using one of these cables, without using PoE, is wasting a number of wires. In fact, there are now cheaper cables out there that only have four (4) conductors, rather than the full eight (8). So, that brings us to two points. It makes sense that PoE has come into existence, and if you're preparing to use PoE devices, be sure you run cabling that will handle both data and power.

In PoE, there are a number of abbreviations commonly used:

Abbreviation Meaning Description
PD Powered Device Any networked device receiving PoE
PSE Power Sourcing Equipment Devices that send both power and data over Ethernet cable to a PD. Referred to as either "Midspan" or "Endspan".
Endspan or Endpoint A typical example of this is a PoE network switch. It provides power to Powered Devices (PD).
Midspan If a switch is used that doesn't provide PoE power, then a power source will need to be added between the switch and the PD. A common example is a PoE Injector. This is considered a Midspan PSE device.

The benefits of PoE are numerous, as you can imagine. Rather than having every camera in an installation require the use of an outlet, a PoE switch using a single outlet can provide both power and Ethernet to a multitude of cameras with a single Cat5 or Cat6 wire going to each. In many cases, Ethernet cabling may already be installed, particularly in commercial installations, thereby lowering installation costs for PoE equipment. Another benefit is that when each powered device is receiving its power from a PoE capable switch, it is often possible to restart a PoE-powered device remotely, without having to go to the device itself.

The IEEE 802.3 standard governs PoE Switches and PoE Injectors. There is no special cabling required with the exception that the standard called Ultra-PoE uses all eight (8) pins of the RJ45 connector, so this would be one instance where a cheaper 4-pin cable would not work.

The table below shows the IEEE 802.3 standards and their requirements:

PoE Standard Minimum Cable Required Pins Required Supported Modes
IEEE 802.3af Cat5 4-pins or 2 Pairs Mode A, Mode B
IEEE 802.3at Cat5 4-pins or 2 Pairs Mode A, Mode B
IEEE 802.3bt Type 3 Cat5 8-pins or 4 Pairs 4-pair
IEEE 802.3bt Type 4 Cat5 8-pins or 4 Pairs 4-pair

There is a type of cable called CCA or Copper Clad Aluminum. Although this cable is fine for networking, it is not suitable for use with PoE. This is due to the aluminum core. Aluminum doesn't conduct as well as copper and has a higher DC resistance. This causes it to lose more power over distance and to get hotter. When working with PoE, stick with 100% copper cabling.

One of the things you may find difficult about using PoE is figuring out if you have enough power from the PSE for a PoE device. These specs are usually listed in Watts, rather than in the available current, which can further complicate things. Here, knowing which standard each device uses is most helpful.

Below, see the various PoE standards, and the power both supplied and required for each:

PoE Standard Voltage @ PD Voltage @ PSE Minimum Power for PD Minimum Output @ PSE Maximum Cable Length
IEEE 802.3af 37-57 V 44-57 V 12.95 W or 350 mA 15.40 W 100 m
IEEE 802.3at 42.5-57 V 50-57 V 25.5 W 30 W 100 m
IEEE 802.3bt Type 3 42.5-57 V 50-57 V 51 W 60 W 100 m
IEEE 802.3bt Type 4 41.1-57 V 52-57 V 71 W 100 W 100 m

The variations in voltage and current at the PD (Powered Device) in the table above have to do with the length of the cable run. The longer the cable, the more power is lost. You may have noticed in the above table that the maximum cable length for each PoE Standard is 100 m (328'). This is actually a limitation of both Cat5 and Cat6 cables, as the maximum length of a single run for either type of cable is 100m. The minimum voltage and available power listed above assume a cable run of the maximum length.

So then, what if you need to run a cable further than 100m? For PoE devices, you would add a PoE extender. Specifications may vary, but usually, each PoE extender can add another 100 m of cable length between the PSE and the PD. Usually, each PoE extender is only good for a single PD. Not all PoE extenders are the same, though, and some may not support daisy-chaining, while others do. Check out the specifications of any PoE extender you choose to use if you find yourself in a position to need longer cable runs.


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Today is Alarm Grid's birthday! We're ten years old today. Wow, how time flies. We've weathered lots of things in our ten years. Hurricanes and pandemics just to name a few. To celebrate our special day, we will be closing early today. Our phones are off as of 12:00 pm Eastern Time.

As is always the case, our central station partners are available around the clock, every day. All signals sent by your Alarm Grid monitored alarm system will be handled in the usual manner. If you need to contact the central monitoring station, either to cancel a false alarm or to verify a signal, customers in the United States can contact Criticom Monitoring Services (CMS) by dialing (888) 818-7728 and choosing Option [9].

Canadian customers can contact Rapid Response at (800) 932-3822. Remember any time you contact either monitoring station, you will need to provide your name, your address, and your false alarm password or phrase. If you provide incorrect information when asked it will result in the dispatch of authorities.

If you have a support question about your alarm system or need to make changes to your account, you need to speak with one of our technicians. For those types of requests, send an email to support@alarmgrid.com with as many details as possible about what type of assistance you need. Remember that when we return tomorrow, there may be a tiny support backlog. Please be patient and we will work through all requests as quickly as possible.

I hope you'll join me in wishing a Happy Tenth Birthday to Alarm Grid. We set out to disrupt the traditional alarm equipment and monitoring model, and I think we've accomplished that. It is our strong belief that everyone should have access to professional quality alarm equipment and that you shouldn't have to pay someone else to do what you can do yourself. We've been working toward that end for a decade now. Happy Birthday to Alarm Grid, and many more!!

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On July 5, 2022 Resideo announced that all LTEM-PA, LTEM-PV, LTEM-PIA, and LTEM-PIV communicators will undergo a slightly revised activation process. Upon registration, if the communicator is not using the latest firmware version, it will automatically receive an Over-the-Air (OTA) update.

This announcement came in the form of MyWebTech Technical Notification #83. For those communicators with a WIFI or Ethernet connection, the OTA update will be performed using this communication path. If WIFI or Etehrnet is not available, then cellular data will be used. The update process typically takes about five (5) minutes, but when cellular is the only communication path available, it may take longer. The length of time a cellular upgrade takes also depends on the cellular signal strength.

During the update, the communicator's LED's will light according to where the communicator is in the two-stage process:

  • Firmware Downloading: REG, Status, and Fault LEDs will fast-blink in unison.
  • Upon Firmware Completion: The device will reset, then all five (5) LEDs, REG, Status, Fault, Cell, and WIFI/Ethernet will fast blink in sequence.

The OTA software update will cause the communicator to generate a few different messages to the central station. These messages indicate the beginning and end of the software update process. The messages sent are as follows:

  • E903 - Application Code Update (Remote Download begins)
  • R903 - Application Code Update Restore (Remote Download Completed)
  • E904 - Application Code Update Failure (Remote Download/Update Failed)

For Alarm Grid customers, this notice means that if you are using one of the LTEM-P Series communicators listed above, it is more important than ever that you have your equipment installed and ready when your activation appointment time rolls around. In particular, anyone who will be using cellular communication only, as any OTA update required may take some time to complete, and we currently have no way of knowing how long.

If you have any questions about this notice, reach out to your alarm dealer for details. If you are an Alarm Grid customer, you can send us an email at support@alarmgrid.com. We're here Monday - Friday from 9:00 am - 8:00 pm Eastern time to answer your questions.

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Our offices will be closed on Monday, July 4, 2022 in observance of Independence Day. On this day in 1776, our founders declared our independence from England by formally adopting the Declaration of Independence. Since then, July 4 has become a day to celebrate family and freedom in America.

Our central station partners are available around the clock, every day. All signals sent by your Alarm Grid monitored alarm system will be handled in the usual manner during the holiday unless you've made previous arrangements with us. If you need to contact the central monitoring station, to cancel a false alarm or to verify a signal, customers in the US can contact Criticom Monitoring Services (CMS) by dialing (888) 818-7728 and choosing Option [9].

Canadian customers can contact Rapid Response at (800) 932-3822. Remember any time you contact either monitoring station, you will need to provide your name, address, and your false alarm password or phrase. If you provide incorrect information when asked it will result in the dispatch of authorities.

If you have a support question about your alarm system or need to make changes to your account, the monitoring station cannot assist you with that. For those types of requests, send an email to support@alarmgrid.com with as many details as possible about what type of assistance you need. Remember that when we return after the holiday, there may be a bit of a support backlog. Please be patient and we will work through all requests as quickly as possible.

If you plan to enjoy fireworks as part of your July 4th celebration, be sure to use caution and follow any provided instructions for safety. We'll see you back here after the holiday, hopefully with all our phalanges and eyebrows intact! Thank you for trusting us with your safety, and the safety of your family. We very much appreciate you being a part of the Alarm Grid family.

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