Specification: A set of interfaces Digital switchboard ensures implementation of the following interfaces:
U0 (BRI) - for arrangement of a base access to an individual subscriber's appliance.
U0 (BRI) interface supports:
- distance from a switchboard to subscriber in the range of up to 6 km;
- band width for audio transmittance 6.8 kHz (when using 2B channels);
- subscriber connection with two-wire pair;
- ANSI T1.602 home channel interface, procedure of access to the primary channel, D-channel (LAP1), communication protocol;
BRI/PRI: - signal coding in the line following the diagram 2B1Q according to CCITT recommendation;
- transmittance format PCM 30;
- signal coding in the line following the diagram HDB3 according to CCITT recommendation;
- RS-232 (V.24) for connection of PCs which ensure troubleshooting or a switchboard programming with the speed of up to 115 Kbit/sec;
TDM (2 Mbit/sec, TTL) - for direct uniting of DCN 16U switchboards; E1 (2Mbit/sec, G.703/G.704) - for digital switchboards communication and connection of switchboards to digital automatic switching centers. All switchboard interfaces (except for TDM) have protection against wrong connection of the communication line, power supply and overvoltage. Communication protocols The unit provides support of the following standardized protocols of intercommunication: Q.931 for implementation of a procedure of communication establishment at the network level of OSI model (specification of level 3 for D-channel), provides control over callings and a set of additional services, routing of the service subscriber call with channels commutation; I.452 (Q.932) general procedures for ISDN additional services control; Q.921 (LAP-D) for determination of a frame structure and frame bars content at the channel level of the OSI model (D-channel), network interface of an ISDN user specification of a communicational informational level; I.430 CCITT recommendations (ISDN standard) for arrangement of information transmittance at physical level of the OSI model and base access; I.431 CCITT recommendations (ISDN standard) for arrangement of information transmittance at physical level of the OSI model and main access; ANSI T1.604 minimal set of services of a base channel ISDN interface; I.432 CCITT recommendations (ISDN standard) network interface of a user B-ISDN specification of a physical level; DSS1 protocol of station signaling; EDSS1 protocol for information exchange using external digital lines; Requirements to electric power supply Electric power supply being a system component shall be performed from the external DC source with voltage of 48 V in accordance with the State Standard 5237-88. Radio-frequency noise voltage in the electrical power supply network of the unit shall meet the requirements of the Group 1.1.2 of the State Standard B25.803-83. The unit ensures hot replacement (connection/disconnection) of subscribers' appliances without cutting off the power supply of a switchboard and necessity of its resetting. There ensured a possibility of remote phantom power supply of subscribers' units (via digital switchboard) from the external power source with voltage of 48 V and the current strength shall not exceed 300 ma. A digital switchboard is protected against incorrect polarity connection of the power source. Electric power consumption Power consumption of a DCN16U digital switchboard does not exceed 20 W (without taking into account phantom power supply of subscribers) and 250 W together with phantom power supply of 16 subscribers' units. Service conditions Air working temperature from +5 C0 to + 40 C0. After transportation in winter with the ambient temperature below 0 C0 the unit shall be kept inside the room at temperature ranging from 10 C0 to 30 C0 within three hours before it will be put into operation. Relative air humidity from 20% at temperature 20 C0 to 98% at temperature 25 C0. Atmospheric pressure from 86 to 106 KPa. Operation inside the rooms with high humidity (more than 98%) or the rooms having current-conducting dust is prohibited. The unit packing ensures safe keeping of a digital switchboard during transportation and storage, according to the State Standard 15150-69, under following conditions: - storehouses without heating system with the temperature from -20 C0 to -40 C0, relative humidity 98% at temperature 25 C0;
- storehouses with heating system with temperature range from 5 C0 to 40 C0, relative humidity 80% at temperature 25 C0.
Overall dimensions and weight Overall dimensions when assembled:
- Width - 493 mm (19")
- Depth 196 mm
- Height 44 mm (1U)
- Weight not more than 2.5 kg.
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