I can't get familiar with PUTCHAR and PUTS

I've got a problem. I've posted it yesterday but it was probably lost in text.

static void Nastav_seriovy_kanal (void)
{
	SCON = 0x50;
	TMOD = TMOD | 0x20;
	TH1 = 0xF4;
	TL1 = 0xF4;
	ES = 1;
	TR1 = 1;
}

static void Preruseni_seriovy_kanal (void) interrupt 4
{
	if (RI == 1)
	{
	    RI = 0;
	    if(SBUF == 'A') putchar('Q');
	}
	if (TI == 1) TI = 0;
}