what is encoder?

[EDIT: 20110523 17:01 CDT - reformat - WDR]

What is encoder in neural networks? is it related to multiple output ? I have initialized my network (300 input, 100 hidden, 300 output) as:

my_netInputs = ones (300,2);
my_netInputs (1:300,1)= -1;  
my_netOutputs = ones(300,2);
my_netOutputs (1:300,1)= -1;  
my_net.outputs{1}.range = my_netOutputs;
my_net.inputs{1}.range = my_netInputs;
my_net.layers{1}.size = 100;
my_net.layers{1:2}.transferFcn = 'tansig'; 
my_net.layers{1:2}.initFcn = 'initnw';

It works fine in NN tool box. Is it correct form for designing encoder?