SMS RI enable hardcoding

[LucasImark]

Hi there,

Is there a way built in to the library to enable a RI pin pulse when receiving a SMS?
I try to hardcode the at command to enable the RI pin of the fona 808 to pulse when receiving a sms.

I write it like that:
fona.write("AT+CFGRI=1");

but I'm getting this error:
invalid conversion from 'const char*' to 'uint8_t {aka unsigned char}' [-fpermissive]

Here is the rest of my code:
`#include "Adafruit_FONA.h"

#define FONA_RST 4
#define FONA_KEY 8

char replybuffer[255];
char PIN[5]="9648";

HardwareSerial *fonaSerial = new HardwareSerial(2);

Adafruit_FONA fona = Adafruit_FONA(FONA_RST);

uint8_t readline(char *buff, uint8_t maxbuff, uint16_t timeout = 0);
uint8_t type;

void setup() {
// put your setup code here, to run once:
pinMode(FONA_KEY, OUTPUT);
digitalWrite(FONA_KEY, HIGH);

Serial.begin(115200);
delay(100);
fonaSerial->begin(115200);

fona.unlockSIM(PIN);

delay(1000);

fona.write("AT+CFGRI=1");//enable RI on SMS receipt
}
`

Board: ESP32
IDE: Arduino 1.8.5
Library version: 1.3.4

thanks for your help
The Iron Mechanic