Bell System (Telephones) Ltd. Presley Way, Crown Hill, Milton Keynes MK8 0ET. Tel: 01908 261106 FAX: 01908 261116 email: sales@bellsystem.co.uk website: www.bellsystem.co.
719S 2 Door Switching Unit General Description The Model 719S Switching Unit provides a means of operating a door entry telephone system from two entrances. Several 719S units may be combined to extend operation up to a maximum of eight entrances. OPERATION When a telephone is called from a given entrance, the switching unit connects the telephone to the speech amplifier ( model 51) of that entrance panel only.
719S 2 Door Switching Unit A maximum of 20, 500X series telephones can be powered directly from a 719S unit. For up to 60 telephones an additional M440 PSU must be used. Refer to diagram 6. For larger systems contact your distributor or the manufacturer for further guidance. ELECTRIC LOCK RELEASE Either fail-secure (AC/DC) or fail-safe (DC only) type electric lock releases can be operated directly from the 719S switching unit. Use the 'FAIL SECR' connections for fail-secure releases.
719S 2 Door Switching Unit SPEECH ACTIVE TIME The duration for which speech remains active (from the moment a telephone is called) can be set between 30 and 120 seconds using the PCB DIP switch marked ‘SW2': Time (s) ‘SW2' DIP Switch setting 3 4 30 off off 60 on off 90 off on 120 on on LOCK TIME The Lock Release time can be set between 3 and 20 seconds using the PCB DIP switch ‘SW2': Time (s) ‘SW2' DIP Switch setting 1 2 3 off off 5 on off 10 off on 20 on on MODE SETTING For
719S 2 Door Switching Unit TEST BUTTON There are two Test buttons on the PCB marked 'TEST 1' and 'TEST 2'. Pressing the appropriate button will force entrance 1 or 2 into an active state for a fixed period (speech active time). Telephone models with privacy must also be buzzed to enable speech. This feature is provided to assist in fault diagnosis during installation and commissioning.
719S 2 Door Switching Unit Important Safety Information Connections to the 240V AC mains supply must be carried out by a qualified electrician or similar competent person, and made in accordance with accepted safety practices. A two-pole switch (as provided by a Consumer Unit or Switch-Fuse) must be included to isolate both Live and Neutral during Installation or Maintenance.
19S 2 Door Switching Unit Installation Initially connect all the equipment to one telephone ONLY. With the power applied, test the system is fully operational. Connect one telephone at a time and test before proceeding.
719S 2 Door Switching Unit CABLE REQUIREMENTS Use standard 0.5mm solid core twisted-pair telephone cable for all telephone connections unless otherwise specified (e.g.BT spec # CW1308). Do not use stranded alarm cable. For optimum speech clarity a twisted-pair should be used for the 'R' and 'O' connections to telephone and speech unit. Avoid running any cables alongside mains or other transmission wiring.
719S 2 Door Switching Unit System Troubleshooting NOTE Voltages below refer to AC for AC telephone systems and DC for DC telephone systems unless otherwise specified. PROBLEM COMMON CAUSE AND ACTION Low speech volume. ! ! ! ! ! Constant tone/feedback when in use. ! ! ! ! ! ! Speech not audible when phone is buzzed. ! ! 'Vol A' or 'Vol B' adjustment required on the Speech Unit. Speech Unit is not tight against the panel grill. Panel grill is blocked. Speech Unit supply voltage low. Check 11.
719S 2 Door Switching Unit Telephone will not buzz. ! ! ! ! ! ! Lock button does not operate release. ! ! ! ! Tradesman/Exit button inoperative. ! ! Lock release operates all the time. ! ! ! ! Faulty 'O' or 'I' line between Switching Unit and phone. AC telephone systems only: Faulty ‘H’ or ‘O’ line between switching unit and panel. As a check, short ‘H’ to ’O’ at the switching unit and try again. Faulty ‘V’ connection to phone.
719S 2 Door Switching Unit Supply voltage low (less than 10V, any system component). ! ! Short circuit. Disconnect power supply loads and check the output is 11.5V-15V . Systematically disconnect components one at a time or isolate floors, etc. until the voltage is 11.5V-15V. Start with connections around the Switching Unit. Cable voltage drop too high. Try doubling up with spare cores. Refer to the CABLE REQUIREMENTS section.
719S 2 Door Switching Unit Technical Specification Size Boxed 238mm x 189mm x 50mm Size PCB Only 177mm x 137mm x 18mm Supply Voltage 11.5V - 15Vrms 50Hz AC or 11.5V - 15V DC Current Consumption 590mA maximum AC or 290mA maxmium DC Fail-secure Lock output Same voltage as AC/DC supply, AC if both present. 500mA maximum.
