BT NTU6 User manual

Operating guide
Private Circuits
NETWORK TERMINATING UNIT 6
KiloStream Private Circuits
International KiloStream Private Circuits

To report a fault with your KiloStream private circuit, please ring your
BT Service Centre on this number:
Please quote:
your circuit type
your circuit number(s)
your end address
For International KiloStream private circuits please ring the number
provided in your customer handover information.
Operating guide
2

Contents
1About this guide 4
2 About NTU6 4
3 The equipment you’ll see 5
Single NTU 5
Multiple NTU 5
Cabling distance 6
4 Getting started 7
Examining the set-up of your NTU 8
Looking at the corrent status of your NTU 12
5 If you have a problem 9
6 Testing your private circuit 10
Using the test menu 10
Testing your terminal equipment 11
Testing the connection from the network 11
Testing the operation of the entire circuit 12
7 How to report a fault 14
Operating guide
3

1 About this guide
This Operating Guide gives you information on the network terminating
unit 6 (NTU6), including:
• What the display means
• How to use the test facilities
• What to do if you have a problem.
2 About NTU6
A dedicated digital private circuit service, offering either data or voice
transmission.
A national private circuit
An international private circuit
Operating guide
4
Customer
Terminal
Equipment
Network
Terminating
Unit
Network
Terminating
Unit
Customer
Terminal
Equipment
KiloStream circuit
Network
Customer's Premises Customer's Premises
Customer
Terminal
Equipment
Network
Terminating 
Unit
Network
Terminating 
Unit
Customer
Terminal
Equipment
International KiloStream circuit
Network
UK Customer's Premises Distant Country Customer's Premises

3 The equipment you’ll see
BT digital private circuits terminate at your premises on a network
terminating unit (NTU) which is provided within the rental price.
Any on-site wiring and equipment beyond the NTU is your responsibility
and maintained by the relevant contractor. This may be BT or an
independent supplier.
One of our engineers will connect the NTU to the BT network. If you
alter the line connections in any way, you will set off remote alarms
within the BT network and your service may be affected
Single NTU
If you’ve ordered a single circuit, the unit is contained in a blue
rectangular box. The lamps on the front of the unit, in conjunction with
the liquid crystal display (LCD), show the operating state of the circuit.
Front view of KiloStream NTU6 single unit
Multiple NTU
If you’ve ordered a number of lines, or a network of services, you will
need a multiple NTU. This normally consists of a series of NTUs in
‘card’ form. Each ‘card’ will be shelf mounted in a stacking system.
Operating guide
5
RX NRDY RXD
TM
FAULT
TOGGLE PROG
MENU SCROLL TX NRDY
Liquid Crystal Display

There is only one LCD for a shelf of multiple NTUs. To select the NTU
for which you want to display details on the LCD, press the appropriate
DISP button. A yellow LA lamp confirms the NTU you’ve selected.
The LCD will continue to show information from that NTU until you
press another DISP button.
Front view of NTU6 shelf mounted unit
Cabling distance
To achieve the best performance from your circuit, the cabling distance
between the NTU and any data terminal equipment (DTE) shouldn’t
exceed 180 meters. If you relocate the DTE at any time, please ensure
that you don’t exceed this distance.
Operating guide
6
Yellow lamp
FAULT
TM
LA
FXD
DISP
RX
NRDY
Button
Yellow lamp
Power Unit
Button
Display Unit
TX
NRDY
Liquid Crystal
DisplayNTUs
Blanking panels over
vacant spaces

4 Getting started
When we connect your private circuit, the LCD will show one of three
menu headings: , or .
To rotate the LCD to the menu you require:
• press the up or down Scroll button.
When you see the > symbol on the right of the LCD display, there are
further options available within the menu. To see these further options:
• press the Menu button.
When your circuit is provided, depending on the type of circuit and the
conditions at the distant end, the menu will show one of the
following messages, and a light may also be illuminated:
Whenever a binary 1 is present in the recieved data, the RXD light will
be illuminated.
STATUS
TEST
STATUSOPTIONS
Operating guide
7
circuit type message you see light illuminated
X.21 64kbit/s /56kbits S: NTU READY –
X.21 2.4-48kbit/s S: NTU NOT READY RX NRDY
X.21 bis (v.24) cct. S: NTU READY RXD
108/1 held high by BT
X.21 bis (v.24) cct. S: NTU NOT READY RX NRDY
108/1 under your control

Examining the set-up of your NTU
You can use the OPTIONS menu (which is display-only) to examine the
set-up of your NTU. There are six messages:
0: X21/X21 BIS 0: 105 SET ON 0: 106 DELAY
0: 107=108/1 0: 108/1 SET ON NO X21 OPTIONS
If your NTU is set for X21, press the up or down Scroll button to see the
NO X21 OPTIONS message.
Looking at the current status of your NTU
You can use the STATUS menu (which is display-only) to examine the
current operational status of the NTU in its normal state. There are six
messages:
S: LOOP ACTIVE S: NTU NOT READY S: NTU READY
S: SEND DATA S: RECEIVE DATA S: DATA TRANSFER
The NTU display will always revert to one of the messages above when
you press the up or down Scroll button.
Operating guide
8

5 If you have a problem
If you think there’s a problem with your KiloStream private circuit or with
your NTU, please try the checks below: you may be able to solve the
problem.
If a fault proves to be in your terminal equipment or on-site wiring, rather
than in the private circuit, BT reserves the right to charge for time spent on
a visit to your premises: it’s in your interest to carry out these checks first.
Operating guide
9
if you see the cause is you should
no lights illuminated no power to the NTU switch the power on and check
and a blank LCD all connections
and a fault on the circuit check all connections to the NTU
FAULT light illuminated and then report the fault to the
relevant Service Centre
and the TX NRDY button or local ask the distant end user to check
FAULT and RXD lights loop has been operated at
illuminated the distant NTU
and the distant data terminal ask the distant end user to check
RX NRDY light illuminated equipment (DTE) is not
connected
a remote loop has been ask the distant end user to check
and TM light illuminated activated at the distant end
and the TX NRDY button has deselect the TX NRDY button
TX NRDY and RXD lights been operated on the local
illuminated NTU
and the local DTE is not raising check with your DTE supplier
RXD light illuminated a ‘request to send’ signal
S: RECEIVE DATA
S: RECEIVE DATA
S: LOOP ACTIVE
S: NTU NOT READY
S: NTU NOT READY
S: NTU NOT READY

Testing your private circuit
Using the Test menu
You can test the circuit and the operation of your NTU by using the
TEST MENU . You can implement the following conditions, which may help
you isolate faults in either the BT network or your terminal equipment.
All the tests, except the self-test and the lamp test, interrupt data flow.
Operating guide
10
select to
loop your NTU towards your terminal equipment (see below)
loop your NTU towards the distant end (see below)
run a self-test on the NTU; if the NTU doesn’t pass it locks with
the message and you should report this to the
relevant X-Stream Service Centre
to cause the distant end to provide a loop back – only possible
where the NTU is set for X21 bis working (see below)
transmit binary 1s to the distant end
transmit binary 0s to the distant end
illuminate all lights on the NTU
T: LAMP TEST
T: SEND BIN 0
T: SEND BIN 1
T: REMOTE LOOP
T: SELF TEST
T: LOOPBACK
T: LOCAL LOOP
SELF TEST FAIL
NTU NTU
Remote siteLocal site
Local end Local endDigital
network
main link
LoopbackLocal
loop Remote
loop
Local
exchange Local
exchange
Types of Test Loops
For national KiloStream circuit