C H A P T E R 3 C O N F I G U R I N G V 1 0 0
V100 Versatile Multiplexer Technical Manual Version 2.2
Page 59 of 231
modem relay to operate, and “STU” permits only the STU-IIB/STU-III relay to operate (if the card is
fitted).
INTERFACE
When the interface type is set to “FXS”, the port provides DC loop current or ring voltage for driving a
telephone or a trunk port on a PABX, while “FXO” configures the port to accept DC current or ring voltage;
both types are 2-wire interfaces. When set to “TIE-LINE”, the port is configured as a 4-wire E&M port and
should not be connected to network voltages.
ALGORITHM
The wide range of voice algorithms allows a trade-off between voice quality, delay and bandwidth. It is
possible to select a different coder in each direction, with the sending coder forcing the choice of receiving
coder; this allows different bandwidth to be used according to which end makes the call.
GAIN
Analogue voice applications often require adjustment to optimise the speech quality. This can be caused
by poor line impedance matching, signal loss and echo across the telephone network. A combination of
input and output gain adjustment over a wide range allows the user to achieve the clearest line,
consistent with echo cancellation. At the far end, input gain should be adjusted down to the lowest level
which cancels any echo, then the near end output gain adjusted to compensate for the overall signal level.
DESTINATION
When a voice channel destination is specified as “AUTO”, calls made on this channel will be automatically
routed to the dialled destination port according to the DTMF or E&M signalling received. It is also possible
to set up fixed destinations, as in the example above, by entering the specific address of the destination
V100 port. This feature is useful when configuring Tie-lines between PABXs, or “hotlines” between
telephones and avoids the need for the user to enter any dialling digits just to route through the V100
network.
Using the Directory menu it is possible to specify personalised numbers instead of V100-style port
numbers. This allows an existing network numbering scheme to be used with the V100, as well as
permitting the use of node numbers greater than 9.
The parameters and options are shown in the following table:
Field Options
Description
CHANNEL
Information only
Displays the numbers of all data channels installed.
CLKREF GRXCLK,
GTXCLK
Clock reference bus used by the voice card PLL
DTMF,
DTMF signalling passed. All relays enabled
SIGTYPE
E&M,
E&M signalling passed. All relays enabled