As an ISDN standard
network termination, an NT device is normally provided in a wall-mounted
enclosure with a connecting cable to be plugged into a line socket and
can be fed from the 220 VAC mains.
Our alternative
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the world's smallest ISDN-NT!
The NT micro in brief
# A new circuit concept using state-of-the-art components as well as
# consistent adaptation of its design to standardised installation systems
have facilitated
# the integration of this network termination into a line socket.
# The NT micro is the flush-mounted version of an ISDN standard network
termination and, logically,
# the NT micro also has been prepared for S-bus line buried installation.
# The NT micro is easy and simple to install by the use of plug-in spring
terminals, but even so,
# the function of the NT micro corresponds to a conventional standard
network termination in every respect.
# Patent pending for the NT micro.
Particular benefits of the NT micro
Due to the integration of this network termination into a line socket,
it is not necessary to install an additional unit - the external NT -
at the subscriber's. This, at last, removes out of sight a unit that is
often found disturbing in living areas, just because of its mere cabling
and space demand. So far, this has also resulted in postponement of the
decision to change over to ISDN. It largely goes without saying that installation
efforts and costs will reduce.
1. Interfaces
1.1. S0 interface At the S0
interface, several ISDN terminals of various services can be connected
via two balanced twin wires. In parallel with S0
RJ 45 sockets , plug-in spring terminals are provided for buried installation
of the S-bus.
The operation modes "short passive bus" and "point-to-point connection"
are available. The termination of the transmitting and receiving direction
is removeable (standard configuration).
1.2. UK0 interface The NT micro must be connected
to a two-wire line. Depending upon the cable types and wire diameters
used, transmission ranges of up to 8 km are possible. At its underside,
the NT micro has a plug-in spring terminal for the easy connection of
the two-wire exchange line.
2. Integrated Functions
2.1. Remote supply converter
The remote supply converter produces from the remote supply voltage the
operating voltage for the UK0 / S0
modules as well as a supply power of at least 420 mW for a rated voltage
of 40 V to feed the S0 interface. Between the UK0
and the S0 interface, potential segregation with
a test voltage dielectric strength 2 kV is implemented.
2.2. Power supply unit For the majority of applications, the supply power
of 420 mW (restricted supply) of the exchange via the NT micro is sufficient,
as most of the ISDN terminals have their own power supply. However, if
a supply power of 4.5 W is required (normal supply), an attached plug-in
power supply unit can be used. You will just have to insert the RJ11 connector
of the plug-in power supply unit into a socket of NT micro. The function
of the plug-in power supply unit fully meets the requirements of ITU-T
Recommendation I.430 (1 TR 216).
2.3. APS detector
At the S0 interface, the NT micro provides a supply voltage, whose polarity
corresponds to the "restricted" mode. The NT micro contains a circuit
which detects whether a voltage having the "normal" mode polarity and
being produced by an externally connected APS (auxiliary power supply)
or by the plug-in power supply unit is available at the S0
interface. In such a case, the internally produced 40 V restricted mode
voltage will be disconnected from the SO interface.
2.4. Visual signalling
There is a green LED inside the NT micro. This LED indicates the presence
of the remote supply voltage from the exchange. The LED can be seen through
the two RJ11 sockets and is required for service purposes only.
3. Specifications
U Interface 4B3T
as per:
ETSI TS 102 080, 1TR220
Transmission method: Two-wire duplex operation with echo compensation
Channel structure: 2B + D16 + synchronisation + service data
Line code: 4B3T
Overall transmission speed: 120 kbaud
Transmitting amplitude: 2 VS0 ± 10 % single pulse at 150 W
Internal resistance: 150 W
Return loss: 12.5 kHz ... 50 kHz ³ 16 dB
Line: Balanced copper twin wire
Transmission range at BER £ 10-7 > 4.2 km for 0.4 mm dia.
and a noise ratio of 10 mV/ÖHz > 8.0 km for 0.6 mm dia.
Degree of safety: TNV circuit (EN 60 950)
Remote
power supply DC voltage: 28 V - 99 V =
as per: ETSI TS 102 080, ANSI T1.601
Transmission method: Two-wire duplex operation with echo compensation
Channel structure: 2B + D16 + synchronisation + service data
Line code: 2B1Q
Overall transmission speed: 80 kbaud
Transmitting amplitude: 2.5 VS0 ± 5 % single pulse at 135 W
Internal resistance: 135 W
Return loss: 10 kHz ... 25 kHz ³ 20 dB
Line: Balanced copper twin wire
Transmission range at BER £ 10-7 > 4.2 km for 0.4 mm dia.
> 8.0 km for 0.6 mm dia.
ANSI loops 1-15
ETSI loops 1-8
Degree of safety: TNV circuit (EN 60 950)
Remote power supply DC voltage: 28 V - 120 V =
S/T
Interface
as per: ETS 300 012, ITU I.430, FTZ 1 TR 236
Transmission method: Four-wire duplex operation
Channel structure: 2B + D + synchronisation + service data
Line code: AMI, modified
Sum bit rate: 192 kbps
Transmitting amplitude: 750 mVS0 ± 10% at 50 W
Subscriber installation: Two balanced copper twin wires
Point-to-point: up to 1100m, depending on cable type
Electrical isolation: As per EN 60950
S0 supply: Permanently short-circuit proof
Restricted mode: 420 mW
Normal mode: 4.5 W when optional AC adapter is used
Supply voltage: Restricted mode: + 34 V ... + 42 V
Normal mode: - 34 V ... - 42 V
Terminating resistor: 100 W, ¥, changeable
Degree of safety: SELV circuit (EN 60950)
APS detector:
Detection threshold
Normal supply: < 5 V
Changeover time: < 2.5 ms
Power consumption in normal mode: < 3 mW
AC
adapter
Mains voltage range: 85 V ... 253 V
Frequency range: 48 Hz ... 63 Hz
Power consumption: 9 W max.
Degree of safety: Electrical isolation as per EN 60950
Protective class II
Ambient conditions
Storage as per ETS 300 019, Class 1.2.
Transport as per ETS 300 019, Class 2.3.
Operation as per ETS 300 019, Class 2.3.
To give an obvious impression how easy to install the NT micro the following
parts of the Installation Manual are attached.
4. Extraction from: Installation manual
Before you start installation
The following steps are necessary for the installation:
Removing the line socket
Loosen the fixing screws of the line socket. Pull the line socket out
of the flush-mounted box. Remove the two connected wires.
Connecting the NT micro to the exchange line
Pull terminal block off the NT micro. Push into the terminal block the
wires you have disconnected from the line socket. Make sure not to push
both wires into the same terminal. Then return terminal block to the NT
micro. If the installation is correct, a green LED will be lit inside
the NT micro. This diode can be seen through the openings of RJ11 sockets.
For buried installation of the S0 bus, you can connect the S0 cable to
terminal block. For this purpose, proceed in the same way as for connecting
the exchange line. Then fasten the NT micro in the flush-mounted connection
box.
Power supply
When you connect to the NT micro a system (comfort telephone, private
telecommunications switching system, PBX) that has its own power supply,
check whether all connected terminals are fed by your private telecommunications
switching system. If not, you must use optional plug-in power supply unit
of the NT micro. Insert plug of the power supply into a socket of the
NT micro. Please remember that each unnecessary mains connection needs
electric power and is thus a burden to your purse and to the environment.
This completes the installation. Now you can start up your ISDN terminals.
Connecting your terminals
Connect your ISDN terminals by inserting the corresponding plug into one
of the communication sockets at the front of the NT micro. Further terminals
can also be connected to terminal block. This facilitates buried installation
of the S0 bus. Test the functionality of the NT micro by your terminal
(for programming your terminal, refer to the corresponding manual => pay
particular attention to the multiple subscriber number = MSN settings).
Now your access is ready. If this is not the case, first make sure you
have inserted the plugs correctly and the connection to the exchange has
been established properly. If your ISDN access can, nevertheless, not
be started up, please contact your telecom service. During the business
hours, a competent person will help you.
NT micro maintenance and care
Wipe the NT micro with a dry cloth only. No maintenance will be necessary.
CE conformity declaration
This device meets the requirements of the EU Directives and bears the
CE certification mark: EN 50082-1/01.92; EN 55022/08.94, Limits as per
Class B; as well as EN 60950/92+A1/ 93+A2/93+A3/94; 89/336/EWG, "Electromagnetic
Compatibility"; and 73/23/EWG, "Low-Voltage Directive".
Specifications (in extracts)
Mains connection (with optional plug-in power supply)
Voltage range 85 V - 253 V
Frequency range 48 Hz - 63 Hz
Power consumption 9 W max.
Ambient temperature
Storage / transport -25° C to +55° C
Operation 0° C to +40° C
Dimensions
Enclosure size H x W x D (50 x 50 x 45) mm
Jost Kawczyk, Armin Graf
