User manual ASL INTERCOM PS 155

[. . . ] R PRO SERIES USER MANUAL FOR THE PS 155 SIMPLEX WIRELESS INTERFACE AUDIO LEVEL Low SIDETONE High Level Test tone Level TX CONTROL Release VOX PTT CALL PS 155 wireless interface Power Rx/Tx Receive Send CONTENTS 1. 0 2. 0 3. 0 4. 0 5. 0 6. 0 7. 0 8. 0 9. 0 10. 0 11. 0 12. 0 13. 0 14. 0 15. 0 16. 0 17. 0 GENERAL DESCRIPTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 UNPACKING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 FRONT PANEL CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] The Output Transmit Switch switches the wireless unit from receive to transmit. Depending upon the required function by the wireless unit, two ways of connecting it to the wireless unit are possible. Please refer to section 6. 0 for the proper connections. 13 TRANSCEIVER connector A Sub-D 9 pole connector for the connection of the wireless unit. Audio output - User Manual PS 155 / Issue 1 8 2001 ASL Intercom, Utrecht, Holland. 6 6. 0 THE INTERCONNECTING CABLE Special care must be taken in constructing the interconnection cable. Although ASL-intercom has taken great care in shielding and filtering all RF components from the unit, it is still very important that you use the best quality cables and properly construct any electrical and mechanical construction. · Always use shielded cable(s) for the interconnecting cable. · If possible, use a cable assembly of the wireless intercom manufacturer. · Always use the supplied Sub-D9 connector, this connector is shielded. Both input and output are transformer balanced audio lines. The transformers are DC decoupled by condensers. This is necessary for wireless units that use the presence of a DC resistance, at the input or output, to switch from receive to transmit. In case of asymmetric signals at the wireless unit you may connect the negative signal of the input or output to the ground (pin7). The PTT switch contact An external Push To Talk switch may be connected to the interface. When the TX mode switch (9) is in the PTT position the interface reacts on this external switch. When the pins 3 and 7 of the Sub-D9 are shorted by the PTT switch the interface will switch the wireless unit from receive to transmit mode. The total resistance of the used cable and contact (in closed position) may not exceed a DC resistance of 5000 ohms. The TRANSMIT SWITCH contacts These are located on pins 4, 5 and 6. Most wireless units will need a contact to be closed to change from receive to transmit. The NO contact : This is a contact that is Normally Open, it is closed when the wireless unit needs to switch to transmit mode. In this case you need to use the pin 4, this is the Common pin (C), and pin 5, this is the Normally Open (NO) pin. The NC contact : This is a contact that is Normally Closed, it is opened when the wireless unit needs to switch to transmit mode. In this case you need to use the pin 4, this is the Common pin (C), and pin 6, this is the Normally Closed (NC) pin. In some cases a unit needs to see a special DC resistance. [. . . ] One wire is used as an audio line, one as a power line and the screen of the cable functions as earth/return. Current drive is used for signal transfer. Each station utilises a current amplifier to amplify the microphone signal and place it on the common audio line where, due to the constant line impedance (situated in the power supply between XLR pin 3 and 1), a signal voltage is developed which can be further amplified and sent to the headphones. This principle has three advantages: - the use of a single audio line allows several stations to talk and listen simultaneously. [. . . ]