Arduino Leonardo and GSM Module Problem

Hi…i have a serious problem…im using Arduino leonardo…GTM900b Lite gsm madule and Arduino IDE 1.5…
it doesnt seem to have a complicated hardware connection…
GTM900B Lite has 6 pins…GND…TXD…RXD…VMCU…VDD…PWON…on a side .and 5V…VBAT…GND on another side…
my leonardo is ok and Gtm900b with SimCard an Antenna seems to be working because the netLight flashes every 3sec when i reset it manually (with pin PWON)…the 5V…GND…VDD…are connected properly and TX n RX are connected to pins described as softwareSerial pins (RX,TX) in leonardo…and my wires are tested and ok…BUT…there is no response from GSM module as if there is no serial connection!!
it seems like a silly problem to me but im stuke for a week n couldnt solve it! :disappointed_relieved:
It seems that Sim900 codes should be working on Gtm900…here is my code…

#include <SoftwareSerial.h>
SoftwareSerial GTM(2, 3);

unsigned char buffer[64]; // buffer array for data recieve over serial port
int count=0; // counter for buffer array
void setup()
{

GTM.begin(4800); // the GSM baud rate
Serial.begin(9600); // the Serial port of Arduino baud rate.
while (!Serial) {
; // wait for serial port to connect. Needed for Leonardo only
}

delay(5000);
}

void loop()
{
if (GTM.available()) // if data is comming from softwareserial port ==> data is coming from gsm shield
{
while(GTM.available()) // reading data into char array
{
buffer[count++]=GTM.read(); // writing data into array
if(count == 64)break;
}
Serial.write(buffer,count); // if no data transmission ends, write buffer to hardware serial port
clearBufferArray(); // call clearBufferArray function to clear the storaged data from the array
count = 0; // set counter of while loop to zero
}
if (Serial.available()) // if data is available on hardwareserial port ==> data is comming from PC or notebook
GTM.write(Serial.read()); // write it to the GPRS shield
}
void clearBufferArray() // function to clear buffer array
{
for (int i=0; i<count;i++)
{ buffer*=NULL;} // clear all index of array with command NULL*
}
////////////////////////////////////////////////////////////////////////
BTW there is no compile error and serial monitor works fine if i use somthing like …Serial.Write(“XX”); …or Serial.Print(“XX”); …
and i tried many other codes without serial monitor…like ATD…CGMI…CGMS…and so on…but no reaction from softserial…
Can anyone help with that?!im really fraustrated with it…Thanks.

If you have wired it up as per your illustration then

SoftwareSerial GTM(2, 3);

should be:

SoftwareSerial GTM(7, 8);

Thank for ur attention....i know..the picture is just a sample..i change the code when i change the RX,TX..it is too silly to have a mistake like that..ive tried all Leonardo Digital pins as RX n TX although half of them can be used as RX according to manual..i also tried Serial1(Hardware Serial)..Im sure that connections are properly..the problem is probably about Leonardos Uart or maybe GTMs Uart..