4.1 Function Description

Outgoing Call

The ST is activated by pressing the ALARM button. After that, the ST "seizes" the line and establishes connection with the hotline or dispatching center personnel (for details see Automatic Dialing). During the call establishing, the person in the lift hears the dialing tone, then the DTMF dialing tones and the ringing tone, or "Wait please, connection is being made", or any other suitable message.

The message usually starts with the "Wait please, connection is being made" statement and may include the ST identification (address, lift number, etc.). Once the dispatching service answers the phone, the parties can start talking with each other.

Checking Call

The Checking Call is an automatic outgoing call whose purpose is to check the ST function. If activated, the function runs every 72 hours (3 days). The procedure is similar to that of an outgoing call. The difference lies in that a different message is played back, e.g. "Checking call", and a different set of numbers may be used.

Checking calls are typically received automatically – in case the dispatcher's centre is equipped with the 2N^® Lift8 software. A standard PC with VoIP account is required.

Incoming Call

The dispatching center can also call the ST number. The ST answers the call after two rings (the count of rings is parameter-defined) and sends a sound signal. Now, for example, the person trapped in the lift keeps informed about rescue operations. Also, it can be checked remotely whether the ST has been connected and works.

Protection against Unintentional Initiation

Since the main purpose of the ST is to call help in case of emergency (whenever a person gets trapped in the lift), any call can be regarded as unnecessary, if the lift cabin door is open. So, where available, a door contact can be connected to the ST input labeled as CANCEL and a delay can be programmed for the ST to make connection after the ALARM button is pressed. Therefore, in case someone presses the ALARM button by mistake, the lift gets to a certain floor during this delay, the door opens and the call is cancelled. Or, it is possible to set the minimum button pressing time to avoid most false ALARM cases.

Automatic Repeated Multiple Numbers Dialing with Confirmation

Up to 6 telephone numbers and the count of dialing repetitions can be stored in the ST memory for the ALARM button (or 2 numbers where no voice recording module is available). The ST thus tries to get through to all numbers stored. Tone dialing (DTMF) is used as the most reliable connection-confirming criterion. The dispatcher must press button  on its telephone (in the DTMF mode). If the called number is busy or nobody answers the phone within a defined timeout, or in other cases (as defined in the table), the ST tries to call the following number from the list until it completes the pre-defined number of cycles. If the number of cycles is 0, automatic dialing is turned off and the ST calls to one number only.

In this mode, the ST repeats the "Wait please…" message (or any relevant user-recorded message) so many times as preset. The message can be muted by pressing button , or confirming connection with button .

The ST default mode is "Speakerphone automatic dialing with confirmation". There are some other modes designed for specific applications, one of them being "Speakerphone automatic dialing without confirmation"; see later.

Evaluation of Situations during Speakerphone Automatic Dialing with Confirmation

Automatic Repeated Multiple Numbers Dialing without Confirmation

This mode can be used wherever no trained staff for automatic dialing with confirmation is available. The called person need not press any button. The two modes have a common set of numbers, count of cycles, identical responses to the busy tone, and so on. 

The difference is that the non-confirmation mode detects the ringing tone and, if this tone is terminated before the pre-defined count of rings is reached, it assumes that the called party has answered and the connection has been established successfully.

Evaluation of Situations during Speakerphone Automatic Dialing without Confirmation

Call Termination (Outgoing and Incoming Calls)

• The busy or continuous tone*) is detected (for PBX call termination).
• 10 ringing tone*) periods are detected (for a change use parameter 954). This is an innovation compared with the earlier model.
• The maximum call length has elapsed – the ST plays back the "Attention, your call is being terminated" message 10 seconds before the end; the call may be prolonged.
• vyprší nastavená maximální délka hovoru – 10 sekund před vypršením ST přehraje hlášení „Pozor, končí hovor", hovor lze prodloužit.
• The  or  character is received.
• The timeout has expired during programming, or upon message recording.
• 30 seconds after switch activation.
• The same button is pressed during an outgoing call that was used for making the call (this function is disabled in the lift version).