# Analogue interfaces (FXO/FXS)

Here you can see the available analogue terminal interfaces and network interfaces. Besides analogue phones you can also connect Group 3 fax machines or modems to analogue terminal interfaces. An analogue terminal interface can also be used as a door intercom, audio input, control input for controlling switch groups 1 to 3, as control output, or for connecting a general bell.

## FXS mode

The 2-wire FXS interface (socket a and b) can also be assigned with other functions besides connecting an analogue terminal. The individual FXS modes and their settings are briefly explained below.

## FXS mode phone / fax

In conventional terminal mode you can connect the following analogue terminals:

- Analogue phones with DTMF or pulse dialling (earth key is not supported)

- Radio units for cordless phones

- Group 3 fax machines

- Answering machines

- Modem

Table 1. FXS mode phone/fax settings
Parameter | Explanation
Ring pattern | The ringing pattern provides a means of identifying whether the call originates from within the PBX (internal call) or from the outside (external call). Certain terminals which automatically answer calls (e.g. fax machines) are not able to interpret the double ringing tone correctly. For analogue interfaces you can use the configuration Ring pattern = Single ringing tone to force the use of the single ringing tone at all times for all calls.
Terminal supports call identification | The communication server is capable of sending the call number (CLIP) of incoming calls to analogue internal terminals. However different CLIPs can only be sent to two analogue terminals simultaneously. So only activate this check box if the analogue terminal on this interface can also detect the CLIP.The method for transmitting the CLIP is configured using the parameter Alerting signal type in the Country settings view.
Fax device | This parameter lets you configure the type of device on the analogue interface: No fax device: Terminal is not a fax device. Voice connection is established. Fax device (T.38): Fax device without voice and voice mail system. For connections via IP a T.38 connection is set up whenever possible. Combo device (voice/T.38): Fax device with voice and/or voice mail system. A voice connection is established first. When transmitting fax data, it is best to switch over to a T.38 connection whenever possible in the case of connections over IP. Fax over VoIP (G.711): Transmitting fax data as voice data on the IP network. The G.711 protocol is always used. Note: This setting can also be made for analogue terminals.

## FXS mode 2-wire door

In this mode two-wire door intercoms with DTMF control functions can be connected. The no-load voltage in this mode is 24 VDC. The loop current is limited to 25 Am.

Table 2. Settings for FXS mode 2-wire door
Parameter | Explanation
Call number | Number of the door intercom
Description (door) | Free text field for specifying the door intercom.
DTMF sequence to open the door | With the DTMF sequence specified here you can control the door intercom to operate the door opener.

## FXS mode control output

If an FXS interface is configured as a control output, the signal can be used to control external devices or equipment (e.g. heating, alarm or outdoor lighting systems). A control output is addressed via its number. The number is of the call number type and it is created in the numbering plan.

Table 3. Settings for FXS mode control output
Parameter | Explanation
Number (control output) | This number is used to address the control output.
Name (control output) | Free text field for specifying the door intercom.
State (control output) | You can see the current state of the control output here.

## FXS mode control input

If two FXS interfaces are configured as the control inputs, then switch group 1 can be switched between positions 1, 2 and 3. An external switch or relay is connected each time here.

Table 4. Settings for FXS mode control input
Parameter | Explanation
Switch position of switch group 1 | The current switch state of switch group 1 is shown here. You can also change the switch state manually here.
Control input 1 | FXS port of the 1st. Control input.
Control input 2 | FXS port of the 2nd. Control input.

Table 5. Connection table
Switching position | Control input 1 | Control input 2
1 | Off | Off
2 | On | Off
3 | On or Off | On

## FXS mode audio source (Mitel 470 only)

One FXS interface per communication server can be configured for connecting an audio device. In this mode the FXS interface becomes an audio input used for feeding in music or a spoken text for the announcement service, voice mail greetings and music on hold.

## FXO interface settings

Table 6. Network interface settings
Parameter | Explanation
Outgoing barred | This network interface is barred for outgoing calls.
Trunk groups | You can assign a trunk group to the network interface here.

Table 7. General settings
Parameter | Explanation
Behind communication server | Activate this setting if this network interface is not directly connected with the exchange but down-circuit from a primary communication server. Digit barring is generally deactivated; the digit barring of the primary communication server has to be used. Incoming calls are forwarded transparently to the user.
Line attenuation | Short/Short D: For lines with a loop resistance below 280 Ohm. Long/Long D: For lines with a loop resistance above 280 Ohm. -D variants are used to increase the volume in an “analogue exchange - digital user” connection type by 3 dB in both directions as this type of connection is generally perceived as too quiet.
AC impedance | The impedance of the analogue exchange line is selected here. This setting varies from country to country and from one network provider to the next. The default settings differ depending on the country set.
Dialling mode | DTMF: Frequency dial PULSE: Pulse dialling Select DTMF if both types of dialling are supported on this exchange line circuit.
Ringing cycle(s) | If the amount of time between rings on the exchange line with incoming calls is longer than the value set here, the internal ring setting is interrupted. This is the case for example when the external caller hangs up.
Dialling-tone detection | The communication server waits for the dialling tone from the exchange before dialling begins.
Dial tone time | Waiting time for the exchange dial tone: If dialling tone detection is activated, the PBX switches over to the next free exchange line once the waiting time has elapsed. If dialling tone detection is deactivated, the dialling begins at the latest once the waiting time has elapsed.
International dialling tone | If an international dialling tone is selected, the dialling process is interrupted after one of 10 predefined digit sequences to wait for the international dialling tone. The sequences can be defined in the International dialling tone view.

Table 8. Settings for the release signal
Parameter | Explanation
Release signal | If a connection is terminated only unilaterally by the external call party, the connection is maintained until the exchange sends a release signal. If a connection is terminated only unilaterally by the external call party, the connection is maintained. High call charges may be incurred. Note: Not all network providers send a release signal.
Release signal type | The type of release signal depends on the network provider. For the Congestion tone setting: The frequency and the time sequence of the congestion tone vary from country to country. Detection is automatically adapted to the set country.
Busy/Congestion tone level | The level of the congestion tone is not necessarily the same on all exchange lines. Lets you adapt the detection to the existing level.

Table 9. Settings for CLIP detection
Parameter | Explanation
CLIP detection | The network provider supports CLIP on this exchange access and the communication server should take it and re-use it. The network provider does not support CLIP on this exchange access.
CLIP detection mode | This is a country-specific setting. FSK: The clip data is transmitted as FSK signal (Frequency Shift Keying). This default setting applies for most countries. DTMF: CLIP data is transmitted with the help of DTMF signals (applies, for instance, to Saudi Arabia).
Alerting signal type | Lets you select the way in which the network provider transmits the CLIP data. No alerting signal: Data transmission takes place between the first and second ring signal. The first ring signal is used as an alerting signal. Ring pulse: Data transmission takes place before the first ring signal. A ring pulse is used as an alerting signal. Dual Tone: Data transmission takes place before the first ring signal. Two successive tones (Dual Tone) are used as the alerting signal. Line Reversal & Dual Tone: Data transmission takes place before the first ring signal. A line polarity reversal is used as the alerting signal, followed by two successive tones (Dual Tone). Not defined: No data is detected.

Parent topic: Access control
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