B-LinkU FAQ
Please note that these FAQ apply to the B-LinkU only. If you do not find the information that you are looking for, please email us and we will be pleased to assist you.
- Does the B-LinkU have two or 4 ports?
- What is the difference between the S/T and the U interface?
- Can I connect one terminal with an S/T interface to another terminal with a U interface using the B-LinkU?
- Do I need an external NT1?
- Which ISDN protocols does the B-LinkU support?
- Do I need a PC host?
- What are the default telephone numbers for each port?
- How do I change the default telephone numbers for each port?
- What do the BRI port LED's show me?
- Is there a limit to how many digits I can dial from one port to another?
- Which switch type should I select on my Cisco router?
- Does the B-LinkU support SPID's?
- What type of cable do I need to connect my B-LinkU to the router's ISDN Interface?
- Some networks expect terminals to retain their TEI after disconnection and some do not, can I set this behaviour on the B-LinkU?
- What will the protocol trace feature show me?
- Does the B-LinkU support channel bonding?
- Can I simulate other network behaviour?
- Can I select particular network call clearing causes?
- Can I test the full operation of just one terminal using the B-LinkU?
- Can B-LinkU simulate leased line operation?
Does
the B-LinkU have two or four ports?
The B-LinkU has two active
ports but it is possible to connect to either
port using the U interface or the S/T interface.
Two bearer (B) channels are available on each
of the two ports.
What
is the difference between the S/T interface and
the U interface?
The U interface is found on the network side of
an NT1 (network termination 1) and the S/T interface
is found on the user side on the NT1. When you
order an ISDN basic rate line in North America
you are supplied with a two wire U interface and
expected to source your own NT1 or connect a terminal
which is fitted with an internal NT1. In Europe
and some non European countries, the network operators
install the NT1 as part of their service so you
are expected to connect to the 4 wire S/T interface
which is found on the user side of the NT1. In
summary, North American customers will usually
connect their terminals to the B-LinkU via the
U interface and European customers will typically use the S/T interface.
Can
I connect one terminal with an S/T interface to
another terminal with a U interface using the
B-LinkU?
Yes, the router/terminal with a U interface (internal
NT1) should be connected directly to one B-LinkU
port via the U interface. The terminal with an
S/T interface (no internal NT1) should be connected
directly to the other B-LinkU port via the S/T
interface.
Do
I need an external NT1?
If your terminal has an internal NT1 then this
may be connected directly to the U interface on
the B-LinkU. Terminals which do not have an internal
NT1 should be connected directly to the S/T interface
or to the U interface via an external NT1.
Which
ISDN protocols does the B-LinkU support?
B-LinkU supports a subset of the ETSI Euro ISDN
protocol and a subset of the National ISDN 1/2
protocol. (ETSI Euro-ISDN is used in most European
countries as well as some non European countries,
Australia and a number of countries in the Far
East).
Do
I need a PC host?
A PC host is only required if you wish to change
the default settings such as telephone numbers
for each port or to access the protocol trace
function. If you want to use the B-LinkU without
a PC host the default telephone numbers for each
port can be found in the user guide supplied on
CD ROM with your B-LinkU and also detailed in
these FAQ.
What
are the default telephone numbers for each port?
Port 1 (B1 & B2): 1111
Port 2 (B1 & B2): 2222
How
do I change the default telephone numbers for
each port?
Having loaded the B-LinkU configuration software
onto your PC host, connect the B-LinkU to your
PC host via the serial port and launch the program.
Click on the Port 1 tab and enter the required
telephone number in the Single number area. (The
default numbering mode is Single Number where
the same telephone number is dialled for B1 and
B2). Then repeat this process for Port 2.
What
do the BRI port LED's show me?
Each port on the B-LinkU has two bi-coloured LED's
which will give you all the information you need
to confirm successful operation. On the BRI ports
the top left hand LED illuminates orange when
the connected terminal has synchronised with the
network clock. The top right hand LED illuminates
orange when layer 2 is established (TEI requested
and assigned). Both of these LED's will stay orange
until a call is sent or received at which time
they will change to green to indicate which bearer
(B) channel/s are in use. The top left hand LED
illuminating green indicates B1 and the top right
hand LED illuminating green indicates B2. A separate
LED on the front panel illuminates to show the
presence of phantom power (PS1).
Is
there a limit to how many digits I can dial from
one port to another?
In the B-LinkU software within the Port 1 or Port
2 tab you are allowed to enter 20 digits which
will be more than enough for most applications.
If a longer number is required then you can enter
a further 10 digits using the Unit tab and entering
up to 10 digits in the Exchange Prefix area. This
can be considered as a 'dialling code' for the
B-LinkU and it extends the maximum number of digits
available to 30. The exchange prefix number should
always be different to the number of each port
and need only be dialled if you wish to test long
numbers.
Which
switch type should I select on my Cisco router?
The B-LinkU defaults to using the ETSI Euro-ISDN
protocol (basic- net3). If you would like to use
SPIDS, change the switch type to US NI 1 in the
Unit tab, and select support for basic - NI on
your router.
Does
the B-LinkU support SPID's for National ISDN 1/2?
Yes. The B-LinkU allows the user to enter one
SPID value for both ports or one SPID value for
each port. Although several SPID values may be
entered in this way, the B-LinkU only supports
one service profile which allows any type of terminal
to respond to any type of call.
What
type of cable do I need to connect my B-LinkU
to the router's ISDN Interface?
An RJ.45 straight through patch cable (an Ethernet
CAT 5 patch cable will do the trick).
Some
networks expect terminals to retain their TEI
after disconnection and some do not, can I set
this behaviour on the B-LinkU?
Yes, if you are experiencing any terminal activation
problems carry out the following: From the main
Unit tab select Advanced and click on the TEI
Activation button, then click on the tick box
to select Remove TEI on PH Deactivation.
What
will the trace feature show me?
The trace feature provides a full 'English' decode
of the ISDN signalling (D channel) between the
network (B-LinkU) and each of the connected terminals.
When a new terminal is connected you will see
the information state exchanges which result in
synchronisation between the network and the terminal.
If a terminal deactivates at any time during or
outside a call you will immediately capture this
behaviour for debug purposes. Once Activation
is achieved you will see layer 2 functions such
as terminal endpoint identification (TEI) being
requested and assigned followed by receiver ready
(RR) exchanges between the terminal and the network
port confirming that both ends are ready to receive
calls. When a call is made you will see a full
decode of the layer 3 call control messages and
all of the content. For those who understand the
ISDN protocol this information is an invaluable
way to debug any interoperability problems or
protocol errors. Filters are provided to remove
layers, messages and ports from the display if
required.
Does
the B-LinkU support channel bonding?
Channel bonding is a function of the ISDN terminal
not the network. B-LinkU allows all bearer channels
to be operational on all of the basic rate ports
so the user just needs to dial once, twice or
more depending on the number of channels required
and the number of channels available on the B-LinkU.
Can
I simulate other network behaviour?
B-LinkU supports a subset of the ETSI Euro-ISDN
protocol and a subset of the National ISDN 1/2
protocol. All networks which use ETSI Euro ISDN
basic call control procedures may be simulated
with the B-LinkU. This includes some European
Networks which drop layer 2 and layer 1 immediately
at the end of a call, a feature that development
engineers will find very useful. Network behaviour
adjustments are possible by selecting the Unit
tab, then Advanced and from within the Advanced
window, select Timers.
Can
I select particular network call clearing causes?
Yes, B-LinkU is pre-configured with a range of
telephone numbers that may be dialled to invoke
different network clearing causes so that a terminal's
response to these can be fully tested. (To view
these numbers click on the Unit tab). On the protocol
trace you will see the call setup message arriving
from the terminal with the telephone number dialled
and then the response from the network. All these
features are very useful for development, training
and test purposes.
Can
I test the full operation of just one terminal
using the B-LinkU?
Just one terminal may be connected to either of
the ports available on the B-LinkU unit. Simply
dial 4000 from the terminal and you will see that
the B-LinkU accepts this call. If you dial 4000
again the B-LinkU will also accept this second
call (as long as there is a channel available)
and it will place a data loop between transmit
and receive in each of the active channels so
that any data sent by the connected terminal is
returned. The big advantage of this, is that it
allows the user to test the full operation of
just one ISDN device and if it is a video conferencing
terminal, the user will see his own image appear
on it's display.
Can
B-LinkU simulate leased line operation?
Yes, B-LinkU allows the user to 'nail-up' B channels
on any of its ports while leaving the other B
channel(s) available on-demand. To use this feature
select the Unit tab, then Advanced and then Nailed
Up Channels.