function IL=VDSLIL(loopno,freq,len)
%VDSLIL - Get get insertion loss given an ETSI VDSL loop, 
%         a freq. axis, and a length.
%
% Parameter:    loopno     Loop number to test
% Parameter:    freq       Frequency for test [Hz]
% Parameter:    len        Length of loop [m]
% Returns:      IL         Insertion loss [dB]
%
% Example(s):
%               % Insertion loss @ 300kHz for Loop#3 with a length of 2840m:
%               VDSLIL(3,300e3,2840)
%               % Find the reach for insertion loss 40.4069 @ 300kHz:
%               fzero(inline('VDSLIL(1,300e3,x)-40.4069'),2000)
%% ===========================================================================
 
%% ===========================================================================
% Copyright (C):
%       2001-2009 by Forschungszentrum Telekommunikation Wien, Austria;
%                                                         All rights reserved.
% Project       : B1, FTW
% Author(s)     : Tomas Nordstrom (Tomas.Nordstrom@FTW.at)
%
% CVS:       $Id: VDSLIL.m 752 2009-01-02 13:03:52Z tono $
%% ===========================================================================

%% ===========================================================================
% Change History
%      2001-07-03 (ToNo) Created
%      2002-01-25 (ToNo) Changed the IL calc to be more direct
%      2003-11-03 (ToNo) Lists now use cell arrays for both Octave and Matlab
%% ===========================================================================
global ex;

nomodems = 20+1;

tt.name=sprintf('ETSI VDSL Loop %d len %.0fm',loopno,len);
switch loopno
 case 1, cable='BT_dwug';  % TP100
  tt.topology={{0,  '', 'CO', ''},...
               {len,  cable, 'N1', sprintf('%.0f m TP100',len)}};
  tt.traffic={{1, 2, 'VDSL', nomodems}};
 case 2, cable='KPN_L1';  % TP150
  tt.topology={{0,  '', 'CO', ''},...
               {len,  cable, 'N1', sprintf('%.0f m TP150',len)}};
  tt.traffic={{1, 2, 'VDSL', nomodems}};
 case 3,
  tt.topology={{0,  '', 'CO', ''},...
               {70,  'KPN_R2', 'E', sprintf('%.0f m TP100x',70)},...
               {len-70,  'KPN_L1', 'N1', sprintf('%.0f m TP150',len-70)}};% TP150
  tt.traffic={{1, 3, 'VDSL', nomodems}};
    otherwise
        estr=sprintf('Loop #d not implemented\n',loopno); error(estr);
end;

segs    = length(tt.topology);
IL      = -getIL(ex,1,segs,tt.topology,freq,ex.param.Zterm);