¡ Please help ! I'm becoming crazy

[smxabi]

I'm starting with an alarm project but the the beginning cannot be worse. I have a GSM modem wavecom compatible and the prototype board PIC16F877A from CCS.

Firs test: With the hyperterminal of win i type ATD639XXXXXX; and my phone ring how I expected

Second test. I connect the prototype board to the modem. In he Pic I load the following and simple programm:

#include <16F877A.h>
#device ICD=TRUE
#include <string.h>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)
void main()
{
output_low (PIN_A5);
printf("ATD639xxxxxx;\r\n");
delay_ms(15000);
output_high (PIN_A5);
printf("ATH\r\n");
}

¡¡¡ Nothing happen !!!

Thirt test: I Connect the rs232 cable of the prototype board to the hyperterminal of windows. I Push the reset button and in the screen appears the message AT639xxxxxx;

Four test.

I Build a simple Visual basic program :
Is identical to the pic programm. Dials a number

Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
Dim dwMilliseconds As Long

Private Sub Form_Load()
MSComm1.CommPort = 0 ' seleccionamos com1
MSComm1.Settings = "9600,N,8,1" ' parameters for FBUS
MSComm1.PortOpen = True
End Sub
Private Sub command1_click()
MSComm1.Output = "ATD639xxxxxx;" & vbCrLf
Sleep (15000)
MSComm1.Output = "ATH" & vbCrLf
End Sub

and the phone rings

what is happening

I am very confused
Please help
Thank´s in advance from Spain

[rberek]

Use a null modem cable when you connect the proto board to the modem.

[PCM programmer]

Also, add the changes shown in bold below:

[smxabi]

To rbereck:
Null modem. Is the first thing I had made. Everything looks the same.
To PCM Programmer:
I have made the changes that you suggest. Unfortunately I can hear my phone receiving a call.
I had suspected to the max232 if it only transmit but don´t receive but I make a little programm and works fine

#include <16F877A.h>
#fuses hs,NOWDT,NOPROTECT,NOLVP
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=pin_C6, rcv=pin_C7)

void main() {


while(true)
{
putc(getc());

}

}
I can receive by siow all I type
I have testing the voltage from pin 2 and 3 of the serial port. I have -9.2 volts at pin 2 and aproximatly the same at pin 3
Any suggestion, please ?
And a lot of thank´s by the quick answer

[ckielstra]

I suspect your null-modem cable is wired different from your modem requirements. A simple null-modem cable only uses Tx, Rx and Gnd. Many modems also need a signal on their DTR input and sometimes also on the CTS input.

Is your null-modem cable wired like this one? http://www.lammertbies.nl/comm/info/RS-232_null_modem.html#loop

[smxabi]

I`m very glad for helpul information from Rbereck and Ckielstra. Something I was making bad and finally a NULL MODEM has resolve my problemm. ¡ Rbereck your are right when you say that and 9/10 troubles could be resolve with null modem. !
The null modem I make has the following configuration and works fine:

2 3
3 2
5 5
1 + 4 + 6 (shorcut in connecto one)
1 + 4 + 6(shorcut in connecto two)
7 + 8 (shorcut in connecto one)
7 + 8 (shorcut in connecto two)

Thank´s a lot for all people of the foro who help me