User manual ASL INTERCOM PS 278

[. . . ] By changing the position of internally mounted jumpers, it's also possible to hear channel A + B on the left can and the AUX program signal on the right can. The PS 278 is designed to be a master unit in an ASL intercom system and can be used in portable as well as fixed applications. It incorporates a dual channel intercom line power supply, a dual channel headset station, an audio input and uses only 1U of 19" rack space. This makes the PS 278 very versatile and ideal for use in applications where standard microphone cable is available and ease of setup is of paramount importance. Each channel has a Volume (listen level) control, a Talk and a Call button with LED indicators and a sidetone trimmer. [. . . ] A/B/HEADSET routing switches These three switches route the aux input signal to either: 1) Intercom channel A and/or Intercom channel B 2) Directly to the headset If the aux is routed to the headset the aux is for local monitoring only, and can not be routed to the intercom channels. 2 8 9 3 4 5 6 4 User Manual PS 278 / Issue 2 © 1996 ASL Intercom, Utrecht, Holland. 5. 0 FRONT PANEL CONTROLS 10 VOLUME control knobs These knobs adjusts the listen level for the headset. 11 SIDETONE trimmers These trimmers adjust the level of your own voice as you hear it in your headset. Adjustment procedure : - set the trimmer in start position: fully clockwise. Adjusting the sidetone does not affect the level of your voice as it is heard by other stations. 12 TALK buttons These buttons allow you to talk to each channel separately or simultaneously. Latched switching: When a TALK button is momentarily pressed, the microphone will be switched on for the chosen channel and is electronically latched. Momentary switching: When a TALK button is pressed and held, the microphone will be switched on, and when released, will be switched off. 13 CALL A & B buttons These push buttons activate the CALL system. A momentary push will send a CALL signal to all stations connected to that intercom channel and the CALL LEDS will start flashing. Press and hold the buttons for 2 seconds will activate the call buzzer, if not muted. After the CALL button is released the LEDS will continue to flash for a further 2 seconds. 14 HEADSET connector A XLR-4 type connector for the connection of the local headset. This must have a can impedance of 200 ohms (or greater), or each 400 ohms minimum when in parallel. phones The wiring is such that both headset cans are connected in parallel and receive the same signal. As an option, a XLR-6 type connector can be fitted to give a binaural headset configuration where a different signal will appear on each can. See section 7. 1 Internal Jumpers and Controls. User Manual PS 278 / Issue 2 © 1996 ASL Intercom, Utrecht, Holland. 5 6. 0 REAR PANEL CONTROLS & CONNECTORS 15 A & B LINE connectors These XLR-3 type connectors are for connecting the remote-stations, via standard microphone cable. There are two connectors for channel A and two connectors for channel B. XLR pin 1 is connected to the shield of the cable which functions as the common return for audio and power. Since the audio signal is transferred in an unbalanced way, certain rules have to be obeyed when installing the cables of an intercom network. This is to avoid earth loops and to minimize power loss and the possible effect of electromagnetic fields. These rules are: ¼ Use high quality (multipair) cable. For interconnecting user stations, power supplies and accessories in an ASL Intercom network, use high quality shielded two-conductor (minimum 2x 0. 30 mm2) microphone cable only. In case of a multi channel intercom network, use high quality microphone 'multipair' cable only, each pair consisting of two conductors (minimum 2x 0. 15 mm2) with separate shield. [. . . ] If the unit is faulty, it should be sent in it's original packing to the supplier or your local ASL dealer, with shipping prepaid. A note must be included stating the faults found and a copy of the original suppliers invoice. THIS PRODUCT WAS DESIGNED, DEVELOPED AND MANUFACTURED BY : AMPCO SOUND LAB BV MAARSSEN (UTRECHT) HOLLAND User Manual PS 278 / Issue 2 © 1996 ASL Intercom, Utrecht, Holland. 9 12. 0 TECHNICAL SPECIFICATIONS PS 278 POWER SUPPLY mains voltage range 115 V units: 100 - 125 V 60Hz AC 230 V units: 210 - 250 V 50Hz AC DC output voltage +30 V +/-5% DC ripple and noise < 11 mV rms max. output current 1. 7 A continuous / 3 A peak circuit-breaker delay time 0. 2 sec. impedance gain presence filter frequency response V electret mic 30 Kohms (balanced line level) 4. 6 Kohms (balanced mic level) -18 dBu to +6 dBu (line level) -38 dBu to -14 dBu (mic level) +22 dBu (line level) +2 dBu (mic level) +30 V DC (mic level selected) 200 ohms 40 dB - 70 dB (adjustable internally) +6 dB at 5 kHz 200 Hz - 13 kHz (-6 dB) + 9 V DC HEADPHONES DRIVER AMP max. [. . . ]