how can i send 2 value serial

At now this is my code for send 1 thing and receive:

void setup()
{
Serial.begin(9600);
}
void loop()
{
while(Serial.available()>0)
{
t=Serial.read();
switch(t)
{
case 'a': Serial.print (t); break;
}
}

i send number from vb6 to arduino, and arduino send to vb6 what receive.
not important if code in vb6 or other, if other i will try to convert to vb6, i need the idea of code, how can i send 2 thing.