Frequently Asked Questions

Many times designers assume that because a transmitter has a unique address code or protocol that it can transmit at the same time as other units with different codes or protocols. It is important to remember that even though the original signal may be digitally distinct, it enters airspace as an analog electrical signal. This means only one unit can operate at a time without contention. If two people are screaming at you, it does not matter what they are saying, you will not understand either one. The same idea applies to an RF receiver. While protocol or encoding is useful once a signal has been successfully received, it will not be of any use if the signal has been corrupted in the analog domain of free space. A system’s modulation method can also have an impact on its proximity. For example, in most simple AM/OOK systems, everything will be corrupt during overlapping high bit times. In an FM/FSK system, the receiver will lock onto the strongest signal and still provide usable output (assuming a reasonable differential between the two signals).

In some applications, where transmissions are infrequent and not of a critical nature, simply sending data redundantly with randomized breaks can allow the successful operation of multiple units. For applications requiring more reliable transfer, contention must be eliminated through either a sequenced network or through channelization. Either of these methods adds to system cost and complexity, but, when properly implemented, make it possible for the successful operation of multiple units without contention in the same environment.

This is typically caused by a brown-out condition on the decoder where the supply voltage drops below the minimum but not all the way to ground. This condition can corrupt internal registers and cause unpredictable operation. This is often seen as a slow drop on VCC when the system is turned off (possibly because of large capacitors that have a very slow discharge) or the transient drop on VCC due to something in the system. This can be resolved by ensuring the voltage gets to ground within 100ms.

No, the handheld transmitters and keyfobs have not undergone any testing for IP ratings.  They have unsealed holes in the enclosure and are designed for general use.

Yes. As an encoder, it sends whatever address is set by the state of the address lines. When in decoder mode, it rejects packets with all address lines on or all address lines off.

Yes. Products such as our keyfobs, handheld transmitters, and even antennas can be produced in custom colors and cosmetic details, such as housings or keypads, labeled to your custom requirements. There is a one-time NRE charge for setup and tooling and a minimum per order. We can assist with your artwork if needed. Pricing depends on the product, customization and details like the number of colors used, so these are quoted on a case-by-case basis. Contact Linx Technical Support for further details.

The keyfob transmitters and the handheld transmitters all have FCC and Industry Canada transmitter certifications. The 433MHz versions have also been tested and found to conform to the ETSI RED directive.

Yes, the DS Series rejects existing Linx CMD-HHCP-fff, CMD-HHLR-fff, CMD-KEY#-fff and OTX-fff-HH-KF#-HT transmitters where the addressing is set to the default all OFF (or ON) state. This is intentional, to eliminate triggering from unintended transmitters.

The DATA output of the LR Series does not have a strong driver so that the module’s current consumption can be kept low. It can drive 3 or 4 decoders without a problem, but any more than that and a buffer should be used that has a higher drive capability. At this point, there may be other products that are more suitable for the application, so contact Linx Technical Support to go over possible solutions.

Many times designers assume that because a transmitter has a unique address code or protocol that it can transmit at the same time as other units with different codes or protocols. It is important to remember that even though the original signal may be digitally distinct, it enters airspace as an analog electrical signal. This means only one unit can operate at a time without contention. If two people are screaming at you, it does not matter what they are saying, you will not understand either one. The same idea applies to an RF receiver. While protocol or encoding is useful once a signal has been successfully received, it will not be of any use if the signal has been corrupted in the analog domain of free space. A system’s modulation method can also have an impact on its proximity. For example, in most simple AM/OOK systems, everything will be corrupt during overlapping high bit times. In an FM/FSK system, the receiver will lock onto the strongest signal and still provide usable output (assuming a reasonable differential between the two signals).

In some applications, where transmissions are infrequent and not of a critical nature, simply sending data redundantly with randomized breaks can allow the successful operation of multiple units. For applications requiring more reliable transfer, contention must be eliminated through either a sequenced network or through channelization. Either of these methods adds to system cost and complexity, but, when properly implemented, make it possible for the successful operation of multiple units without contention in the same environment.

Many times designers assume that because a transmitter has a unique address code or protocol that it can transmit at the same time as other units with different codes or protocols. It is important to remember that even though the original signal may be digitally distinct, it enters airspace as an analog electrical signal. This means only one unit can operate at a time without contention. If two people are screaming at you, it does not matter what they are saying, you will not understand either one. The same idea applies to an RF receiver. While protocol or encoding is useful once a signal has been successfully received, it will not be of any use if the signal has been corrupted in the analog domain of free space. A system’s modulation method can also have an impact on its proximity. For example, in most simple AM/OOK systems, everything will be corrupt during overlapping high bit times. In an FM/FSK system, the receiver will lock onto the strongest signal and still provide usable output (assuming a reasonable differential between the two signals).

In some applications, where transmissions are infrequent and not of a critical nature, simply sending data redundantly with randomized breaks can allow the successful operation of multiple units. For applications requiring more reliable transfer, contention must be eliminated through either a sequenced network or through channelization. Either of these methods adds to system cost and complexity, but, when properly implemented, make it possible for the successful operation of multiple units without contention in the same environment.