DE503151C - Circuit arrangement for telephone extension systems in series connection - Google Patents

Description

in Frankfurt a. M.

In private branch exchanges facilities are required to be able to transfer In the case of outside calls, the referring office must hang up the handset prematurely before the call is picked up on the part of another body to avoid leading to inadvertent separation of the Conversation would lead. For this purpose, the individual ίο A visual signal (indicator or light bulb) is assigned to the extensions, which is sent by the office switch operated wind.

The invention has for its object to simplify these known systems, and achieves this by giving all extensions a common acoustic signal assigns whose circuit when taking over an outside call in the accepting Body is closed, whereby the signal at the transferring body took place Indicates takeover.

According to the invention, this acoustic signal is brought about by a buzzer which is placed on the contacts of the exchange key and is actuated via a contact controlled by the exchange key of the called station. The connection to the trunk key contacts is the same for all extensions. At the same time, according to the invention, this buzzer can also be used to emit a busy signal when an extension wants to speak to the extension connected to the exchange line.

In Fig. Ι the operation of the circuit is shown schematically. The office key the query wire transfer office is in the working position. In this position is Contact 1 closed and the circuit prepared for the control device. Will . during this process the inquiry or transfer center from another extension, for example, called from extension 2, as shown on the circuit, so the calling extension receives a busy signal. The circuit is as follows:

Minus of the battery across the winding of the

Control buzzer, contact 1 of the pressed switch, line S, contact of extension 2, line S, via normally closed contact 3 of the office switch, hook or hook switch HU ₁ winding of the induction coil, coil D back via normally closed contact 4 of the office switch, line EK back to the positive pole.

In Fig. 2, the takeover of an outside call is shown. After the query, as shown in Fig. 1, the interrogator or remitter presses the contact the desired extension, whereby the exchange switch goes into consultation, and requests the desired extension to take over the call. After Takeover is contact 1, as shown in the drawing at extension ι, closed, the circuit for the control device is restored and the signal is at the Inquiry or referral office audible.

Claims (3)

Patent claims: ι. Circuit arrangement for telephone extension systems in series connection, characterized in that when taking over an outside call from another Extension in the accepting extension the circuit of all Extension units common acoustic signal closed and thereby the completed Takeover of the external call of the transferring unit is displayed. 2. Circuit arrangement according to An-Spruch r, characterized in that all exchange keys of the extension one connected to the circuit of a buzzer Contact (1) received, which with other contacts of the exchange key the accepting and the hook switch of the transferring station completes the buzzer circuit and when picking up the external call is kept closed until the transferring one Position is returned to the idle state. 3. Circuit arrangement according to claim i, characterized in that the Signal circuit used to signal the transfer of office, even when actuated the line selector key of an extension to call another station closed as soon as the called station conducts an outside call, so that the a busy signal is given to the calling station.