There are two instances where a customer may need to connect an autodialler to a digital line.
The behaviour of a digital line provided by a PSTN company (from the point of view of an end user) is, as a standard, as close as possible to a traditional analogue line. Therefore a Memco autodialler can be connected directly to the line.
Where the digital line is provided as part of an IP phone system on a site, an IP to analogue converter (referred to as an Analogue Telephone Adapter or ATA) must be used to interface the autodialler to the digital line.
The ATA will present the autodialler with an interface which is as close as possible to an analogue line. There are several installations with Memco autodiallers using this setup today.
Unfortunately, because of the varied implementations of IP systems from one manufacturer to the next, there is a need to ensure that the chosen ATA is fully compatible with the particular system in use, and because of the rate at which ATA models are replaced by newer versions; Memco is not able to recommend any specific model of ATA.
Customers need to liaise with their IT provider at the installation site in order to ensure the correct ATA is installed and configured. This should be treated in exactly the same way as ensuring a PSTN phone line or GSM connection is available for connection on site before attempting to install an autodialler.
The ATA needs to be configured so that both voice and in-band (data-carrying) DTMF tones can be sent and received reliably. If this cannot be achieved, using the default settings then the ATA should be re-configured using the settings for a fax or modem. If there are still issues the technical support provider for the IP phone system, and/or manufacturer of the ATA need to be contacted.
Another situation to consider when working with IP phone systems is the use case where the autodialler is calling to, or receiving calls from, the “call chain”.
There may be more than one ATA in that call chain and, in that instance, all ATAs in the call chain need to be configured correctly. Check that the IP phone system has also been configured so that DTMF tones are generated on internal calls.
To ensure the autodialler can still dial out in the event of a power failure the IP phone System will require a backup power supply.
In addition, the IP phone system will need to allow external calls to be placed directly to the internal extension assigned to the autodialler. This is to ensure two-way communication can be re-established by the rescue service during a passenger entrapment.
Today a number of companies promote ‘VoIP’, ‘IP’, or ‘digital compatible’ autodialler solutions.
When connecting to an IP phone system, the majority of these solutions also require an ATA to be installed.
Some manufacturers do provide a separate module to connect their autodiallers to an IP phone system. This is promoted as a benefit versus having to provide an ATA.
Given the wide variety of protocols used in IP phone systems, it is advised to thoroughly check the documentation to assure /that the equipment will connect to a specific IP phone system.
If a customer is unable to provide a compatible ATA for their IP phone system an alternative is an installed cellular link.
Connecting to a GSM (Global System for Mobile Communications) gateway or the Memco Digital Communication Platform will allow the emergency elevator telephone to communicate with the rescue service over the cellular network.
If a voice and data gateway is selected there will be the added benefit of data transfer from the lift installation to a remote receiver/monitoring platform.
In January 2018 the European Lift Association (ELA) published an Information Note titled “Hot Topic Planned Upgrading of European Telecom Network systems” which included the following comment:
“GSM networks support a wider range of traditional forms of voice or data transfer than VoIP, and can therefore be seen as a more reliable form of communication.”