Add a bit of documentation on this code, including pointers

to relevant documents and comment on timing issues.

Initial merge of the code in

	http://bugs.digium.com/view.php?id=8586

by Filippo Grassilli (Hyppo) to support
the SMS Protocol 2.

In this commit i have tried to minimize the diffs, so further
code cleanup will come in subsequent commits.


git-svn-id: http://svn.digium.com/svn/asterisk/trunk@48736 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 376 insertions, 36 deletions

diff --git a/apps/app_sms.c b/apps/app_sms.c
index 0fb796109..c6cb93473 100644
--- a/apps/app_sms.c
+++ b/apps/app_sms.c
@@ -16,10 +16,24 @@
 
 /*! \file
  *
- * \brief SMS application - ETSI ES 201 912 protocol 1 implimentation
+ * \brief SMS application - ETSI ES 201 912 protocol 1 implementation
+ * 
+ * \par Development notes
+ * \note The ETSI standards are available free of charge from ETSI at
+ *	http://pda.etsi.org/pda/queryform.asp
+ * 	Among the relevant documents here we have:
+ *
+ *	ES 201 912	SMS for PSTN/ISDN
+ *	TS 123 040	Technical realization of SMS
+ *
+ * \note 2006-09-19: ETSI ES 201 912 protocol 2 used in Italy and Spain
+ *                   support added by Filippo Grassilli (Hyppo)
+ *                   <http://hyppo.com> (Hyppo)
+ *                   Not fully tested, under development
+ * 
  * \ingroup applications
  *
- * \author Adrian Kennard
+ * \author Adrian Kennard (for the original protocol 1 code)
  */
 
 #include "asterisk.h"
@@ -65,9 +79,10 @@ static char *app = "SMS";
 static char *synopsis = "Communicates with SMS service centres and SMS capable analogue phones";
 
 static char *descrip =
-	"  SMS(name|[a][s]):  SMS handles exchange of SMS data with a call to/from SMS capabale\n"
+	"  SMS(name|[a][s][t]):  SMS handles exchange of SMS data with a call to/from SMS capable\n"
 	"phone or SMS PSTN service center. Can send and/or receive SMS messages.\n"
 	"Works to ETSI ES 201 912 compatible with BT SMS PSTN service in UK\n"
+	"and Telecom Italia in Italy.\n"
 	"Typical usage is to use to handle called from the SMS service centre CLI,\n"
 	"or to set up a call using 'outgoing' or manager interface to connect\n"
 	"service centre to SMS()\n"
@@ -75,9 +90,13 @@ static char *descrip =
 	"Arguments:\n"
 	" a: answer, i.e. send initial FSK packet.\n"
 	" s: act as service centre talking to a phone.\n"
+	" t: use protocol 2 (default used is protocol 1).\n"
 	"Messages are processed as per text file message queues.\n" 
 	"smsq (a separate software) is a command to generate message\n"
-	"queues and send messages.\n";
+	"queues and send messages.\n"
+	"NOTE: the protocol has tight delay bounds. Please use short frames\n"
+	"and disable/keep short the jitter buffer on the ATA to make sure that\n"
+	"respones (ACK etc.) are received in time.\n";
 
 /*
  * 80 samples of a single period of the wave. At 8000 Hz, it means these
@@ -105,6 +124,43 @@ static const output_t *wave_out = wave;		/* outgoing samples */
 #define __OUT_FMT AST_FORMAT_SLINEAR
 #endif
 
+#define OSYNC_BITS	80	/* initial sync bits */
+
+/*!
+ * The SMS spec ETSI ES 201 912 defines two protocols with different message types.
+ * Also note that the high bit is used to indicate whether the message
+ * is complete or not, but in two opposite ways:
+ * for Protocol 1, 0x80 means that the message is complete;
+ * for Protocol 2, 0x00 means that the message is complete;
+ */
+enum message_types {
+	DLL_SMS_MASK	= 0x7f,	/* mask for the valid bits */
+
+	/* Protocol 1 values */
+	DLL1_SMS_DATA		= 0x11,	/* data packet */
+	DLL1_SMS_ERROR		= 0x12,
+	DLL1_SMS_EST		= 0x13,	/* start the connection */
+	DLL1_SMS_REL		= 0x14,	/* end the connection */
+	DLL1_SMS_ACK		= 0x15,
+	DLL1_SMS_NACK		= 0x16,
+
+	DLL1_SMS_COMPLETE 	= 0x80,	/* packet is complete */
+	DLL1_SMS_MORE 		= 0x00,	/* more data to follow */
+
+	/* Protocol 2 values */
+	DLL2_SMS_EST		= 0x7f,	/* magic number. No message body */
+	DLL2_SMS_INFO_MO 	= 0x10,
+	DLL2_SMS_INFO_MT 	= 0x11,
+	DLL2_SMS_INFO_STA 	= 0x12,
+	DLL2_SMS_NACK 		= 0x13,
+	DLL2_SMS_ACK0 		= 0x14,	/* ack even-numbered frame */
+	DLL2_SMS_ACK1 		= 0x15,	/* ack odd-numbered frame */
+	DLL2_SMS_ENQ 		= 0x16,
+	DLL2_SMS_REL 		= 0x17,	/* end the connection */
+
+	DLL2_SMS_COMPLETE 	= 0x00,	/* packet is complete */
+	DLL2_SMS_MORE 		= 0x80,	/* more data to follow */
+};
 
 /* SMS 7 bit character mapping to UCS-2 */
 static const unsigned short defaultalphabet[] = {
@@ -186,6 +242,11 @@ typedef struct sms_s
 	unsigned char ibith;         /*!< history of last bits */
 	unsigned char ibitt;         /*!< total of 1's in last 3 bytes */
 	/* more to go here */
+
+	int protocol;                /*!< ETSI SMS protocol to use (passed at app call) */
+	int oseizure;                /*!< protocol 2: channel seizure bits to send */
+	int framenumber;             /*!< protocol 2: frame number (for sending ACK0 or ACK1) */
+	unsigned char udtxt[SMSLEN]; /*!< user data (message), PLAIN text */
 } sms_t;
 
 /* different types of encoding */
@@ -716,6 +777,7 @@ static void sms_readfile (sms_t * h, char *fn)
 				*p++ = 0;
 				if (!strcmp (line, "ud")) {	 /* parse message (UTF-8) */
 					unsigned char o = 0;
+					memcpy(h->udtxt,p,SMSLEN);	/* for protocol 2 */
 					while (*p && o < SMSLEN)
 						h->ud[o++] = utf8decode(pp);
 					h->udl = o;
@@ -1007,6 +1069,216 @@ static unsigned char sms_handleincoming (sms_t * h)
 #define NAME_MAX 1024
 #endif
 
+/*!
+ * Add data to a protocol 2 message.
+ * Use the length field (h->omsg[1]) as a pointer to the next free position.
+ */
+static void adddata_proto2 (sms_t *h, unsigned char msg, char *data, int size)
+{
+	int x = h->omsg[1]+2;	/* Get current position */
+	if (x==2)
+		x += 2;		/* First: skip Payload length (set later) */
+	h->omsg[x++] = msg;	/* Message code */
+	h->omsg[x++]=(unsigned char)size;       /* Data size Low */
+	h->omsg[x++]=0;         /* Data size Hi */
+	for (; size>0 ; size--)
+		h->omsg[x++] = *data++;
+	h->omsg[1] = x-2;	/* Frame size */
+	h->omsg[2] = x-4;	/* Payload length (Lo) */
+	h->omsg[3] = 0;		/* Payload length (Hi) */
+}
+
+static void putdummydata_proto2 (sms_t *h)
+{
+	adddata_proto2 (h, 0x10, "\0", 1);              /* Media Identifier > SMS */
+	adddata_proto2 (h, 0x11, "\0\0\0\0\0\0", 6);    /* Firmware version */
+	adddata_proto2 (h, 0x12, "\2\0\4", 3);          /* SMS provider ID */
+	adddata_proto2 (h, 0x13, h->udtxt, h->udl);     /* Body */
+}
+
+static void sms_compose2(sms_t *h, int more)
+{
+	struct tm *tm;
+	char stm[9];
+
+	h->omsg[0] = 0x00;       /* set later... */
+	h->omsg[1] = 0;
+	putdummydata_proto2 (h);
+	if (h->smsc) {                  /* deliver */
+		h->omsg[0] = 0x11;      /* SMS_DELIVERY */
+		// Required: 10 11 12 13 14 15 17 (seems they must be ordered!)
+		tm=localtime(&h->scts);
+		sprintf (stm, "%02d%02d%02d%02d", tm->tm_mon+1,tm->tm_mday,tm->tm_hour,tm->tm_min);     // Date mmddHHMM
+		adddata_proto2 (h, 0x14, stm, 8);               /* Date */
+		if(*h->oa==0)
+			strcpy(h->oa,"00000000");
+		adddata_proto2 (h, 0x15, h->oa, strlen(h->oa)); /* Originator */
+		adddata_proto2 (h, 0x17, "\1", 1);              /* Calling Terminal ID */
+	} else {                        /* submit */
+		h->omsg[0] = 0x10;      /* SMS_SUBMIT */
+		// Required: 10 11 12 13 17 18 1B 1C (seems they must be ordered!)
+		adddata_proto2 (h, 0x17, "\1", 1);              /* Calling Terminal ID */
+		if(*h->da==0)
+			strcpy(h->da,"00000000");
+		adddata_proto2 (h, 0x18, h->da, strlen(h->da)); /* Originator */
+		adddata_proto2 (h, 0x1B, "\1", 1);              /* Called Terminal ID */
+		adddata_proto2 (h, 0x1C, "\0\0\0", 3);          /* Notification */
+	}
+}
+
+static void putdummydata_proto2 (sms_t *h);
+
+#if 1 /* XXX debugging */
+static char *sms_hexdump (unsigned char buf[], int size)
+{
+	static char *s=NULL;
+	char *p;
+	int f;
+
+	s=(char *)realloc(s,(size*3)+1);
+	for(p=s,f=0; f<size && f<800/3; f++,p+=3) 
+		sprintf(p,"%02X ",(unsigned char)buf[f]);
+	return(s);
+}
+#endif
+
+/*! \brief sms_handleincoming_proto2: handle the incoming message */
+static int sms_handleincoming_proto2 (sms_t * h)
+{
+	int f, i, sz=0;
+	int msg, msgsz;
+	struct tm *tm;
+
+	sz = h->imsg[1]+2;
+	/* ast_verbose (VERBOSE_PREFIX_3 "SMS-P2 Frame: %s\n", sms_hexdump(h->imsg,sz)); */
+
+	/* Parse message body (called payload) */
+	h->scts = time (0);
+	for(f=4; f<sz; ) {
+		msg=h->imsg[f++];
+		msgsz=h->imsg[f++];
+		msgsz+=(h->imsg[f++]*256);
+		switch(msg) {
+		case 0x13:      /* Body */
+			if (option_verbose > 2)
+				ast_verbose (VERBOSE_PREFIX_3 "SMS-P2 Body#%02X=[%.*s]\n",msg,msgsz,&h->imsg[f]);
+			if (msgsz >= sizeof(h->imsg))
+				msgsz = sizeof(h->imsg)-1;
+			for (i=0; i<msgsz; i++)
+				h->ud[i]=h->imsg[f+i];
+			h->udl = msgsz;
+			break;
+		case 0x14:      /* Date SCTS */
+			h->scts = time (0);
+			tm = localtime (&h->scts);
+			tm->tm_mon = ( (h->imsg[f]*10) + h->imsg[f+1] ) - 1;
+			tm->tm_mday = ( (h->imsg[f+2]*10) + h->imsg[f+3] );
+			tm->tm_hour = ( (h->imsg[f+4]*10) + h->imsg[f+5] );
+			tm->tm_min = ( (h->imsg[f+6]*10) + h->imsg[f+7] );
+			tm->tm_sec = 0;
+			h->scts = mktime (tm);
+			if (option_verbose > 2)
+				ast_verbose (VERBOSE_PREFIX_3 "SMS-P2 Date#%02X=%02d/%02d %02d:%02d\n", msg, tm->tm_mday, tm->tm_mon+1, tm->tm_hour, tm->tm_min);
+			break;
+		case 0x15:      /* Calling line (from SMSC) */
+			if (msgsz>=20)
+				msgsz=20-1;
+			if (option_verbose > 2)
+				ast_verbose (VERBOSE_PREFIX_3 "SMS-P2 Origin#%02X=[%.*s]\n",msg,msgsz,&h->imsg[f]);
+			ast_copy_string (h->oa, &h->imsg[f], msgsz+1);
+			break;
+		case 0x18:      /* Destination (from TE/phone) */
+			if (msgsz>=20)
+				msgsz=20-1;
+			if (option_verbose > 2)
+				ast_verbose (VERBOSE_PREFIX_3 "SMS-P2 Destination#%02X=[%.*s]\n",msg,msgsz,&h->imsg[f]);
+			ast_copy_string (h->da, &h->imsg[f], msgsz+1);
+			break;
+		case 0x1C:      /* Notify */
+			if (option_verbose > 2)
+				ast_verbose (VERBOSE_PREFIX_3 "SMS-P2 Notify#%02X=%s\n",msg,sms_hexdump(&h->imsg[f],3));
+			break;
+		default:
+			if (option_verbose > 2)
+				ast_verbose (VERBOSE_PREFIX_3 "SMS-P2 Par#%02X [%d]: %s\n",msg,msgsz,sms_hexdump(&h->imsg[f],msgsz));
+			break;
+		}
+		f+=msgsz;       /* Skip to next */
+	}
+	h->rx = 1;              /* received message */
+	sms_writefile (h);      /* write the file */
+	return 0;               /* no error */
+}
+
+#if 0
+static void smssend(sms_t *h, char *c)
+{
+	int f, x;
+	for(f=0; f<strlen(c); f++) {
+		sscanf(&c[f*3],"%x",&x);
+		h->omsg[f] = x;
+	}
+	sms_messagetx (h);
+}
+#endif
+
+static void sms_nextoutgoing (sms_t *h);
+
+static void sms_messagerx2(sms_t * h)
+{
+	int p = h->imsg[0] & DLL_SMS_MASK ; /* mask the high bit */
+	int cause;
+
+#define DLL2_ACK(h) ((h->framenumber & 1) ? DLL2_SMS_ACK1: DLL2_SMS_ACK1)
+	switch (p) {
+	case DLL2_SMS_EST:	/* Protocol 2: Connection ready (fake): send message  */
+		sms_nextoutgoing (h);
+		//smssend(h,"11 29 27 00 10 01 00 00 11 06 00 00 00 00 00 00 00 12 03 00 02 00 04 13 01 00 41 14 08 00 30 39 31 35 30 02 30 02 15 02 00 39 30 ");
+		break;
+
+	case DLL2_SMS_INFO_MO:	/* transport SMS_SUBMIT */
+	case DLL2_SMS_INFO_MT:	/* transport SMS_DELIVERY */
+		cause = sms_handleincoming_proto2(h);
+		if (!cause)	/* ACK */
+			sms_log (h, 'Y');
+		h->omsg[0] = DLL2_ACK(h);
+		h->omsg[1] = 0x06;  /* msg len */
+		h->omsg[2] = 0x04;  /* payload len */
+		h->omsg[3] = 0x00;  /* payload len */
+		h->omsg[4] = 0x1f;  /* Response type */
+		h->omsg[5] = 0x01;  /* parameter len */
+		h->omsg[6] = 0x00;  /* parameter len */
+		h->omsg[7] = cause;  /* CONFIRM or error */
+		sms_messagetx (h);
+		break;
+
+	case DLL2_SMS_NACK:	/* Protocol 2: SMS_NAK */
+		h->omsg[0] = DLL2_SMS_REL;  /* SMS_REL */
+		h->omsg[1] = 0x00;  /* msg len */
+		sms_messagetx (h);
+		break;
+
+	case DLL2_SMS_ACK0:
+	case DLL2_SMS_ACK1:
+		/* SMS_ACK also transport SMS_SUBMIT or SMS_DELIVERY */
+		if( (h->omsg[0] & DLL_SMS_MASK) == DLL2_SMS_REL) {
+			/* a response to our Release, just hangup */
+			h->hangup = 1;          /* hangup */
+		} else {
+			/* XXX depending on what we are.. */
+			ast_log(LOG_NOTICE, "SMS_SUBMIT or SMS_DELIVERY");
+			sms_nextoutgoing (h);
+		}
+		break;
+
+	case DLL2_SMS_REL:	/* Protocol 2: SMS_REL (hangup req) */
+		h->omsg[0] = DLL2_ACK(h);
+		h->omsg[1] = 0;
+		sms_messagetx (h);
+		break;
+	}
+}
+
 /*! \brief compose a message for protocol 1 */
 static void sms_compose1(sms_t *h, int more)
 {
@@ -1072,20 +1344,31 @@ static void sms_nextoutgoing (sms_t * h)
 		closedir (d);
 	}
 	if (*h->da || *h->oa) {									 /* message to send */
-		sms_compose1(h, more);
-	} else {				 /* no message */
-		h->omsg[0] = 0x94;		  /* SMS_REL */
-		h->omsg[1] = 0;
+		if (h->protocol==2)
+			sms_compose2(h, more);
+		else
+			sms_compose1(h,more);
+	} else {				/* no message */
+		if (h->protocol==2) {
+			h->omsg[0] = 0x17;      /* SMS_REL */
+			h->omsg[1] = 0;
+		} else {
+			h->omsg[0] = 0x94;      /* SMS_REL */
+			h->omsg[1] = 0;
+		}
 	}
 	sms_messagetx (h);
 }
 
-static void sms_debug (char *dir, unsigned char *msg)
+#define DIR_RX 1
+#define DIR_TX 2
+static void sms_debug (int dir, sms_t *h)
 {
-	char txt[259 * 3 + 1],
-	 *p = txt;						 /* always long enough */
-	int n = msg[1] + 3,
-		q = 0;
+	char txt[259 * 3 + 1];
+	char *p = txt;						 /* always long enough */
+	unsigned char *msg = (dir == DIR_RX) ? h->imsg : h->omsg;
+	int n = (dir == DIR_RX) ? h->ibytep : msg[1] + 2;
+	int q = 0;
 	while (q < n && q < 30) {
 		sprintf (p, " %02X", msg[q++]);
 		p += 3;
@@ -1093,17 +1376,23 @@ static void sms_debug (char *dir, unsigned char *msg)
 	if (q < n)
 		sprintf (p, "...");
 	if (option_verbose > 2)
-		ast_verbose (VERBOSE_PREFIX_3 "SMS %s%s\n", dir, txt);
+		ast_verbose (VERBOSE_PREFIX_3 "SMS %s%s\n", dir == DIR_RX ? "RX" : "TX", txt);
 }
 
+
 static void sms_messagerx(sms_t * h)
 {
-	sms_debug ("RX", h->imsg);
-	/* testing */
-	switch (h->imsg[0]) {	/* PROTOCOL version 1 */
+	int cause;
+
+	sms_debug (DIR_RX, h);
+	if (h->protocol == 2) {
+		sms_messagerx2(h);
+		return;
+	}
+	/* parse incoming message for Protocol 1 */
+	switch (h->imsg[0]) {
 	case 0x91:						/* SMS_DATA */
-		{
-			unsigned char cause = sms_handleincoming (h);
+			cause = sms_handleincoming (h);
 			if (!cause) {
 				sms_log (h, 'Y');
 				h->omsg[0] = 0x95;  /* SMS_ACK */
@@ -1119,8 +1408,8 @@ static void sms_messagerx(sms_t * h)
 				h->omsg[4] = 0;	  /* no parameters */
 			}
 			sms_messagetx (h);
-		}
-		break;
+			break;
+
 	case 0x92:						/* SMS_ERROR */
 		h->err = 1;
 		sms_messagetx (h);		  /* send whatever we sent again */
@@ -1157,15 +1446,27 @@ static void sms_messagetx(sms_t * h)
 	for (p = 0; p < len; p++)	/* compute checksum */
 		c += h->omsg[p];
 	h->omsg[len] = 0 - c;		/* actually, (256 - (c & 0fxx)) & 0xff) */
-	sms_debug ("TX", h->omsg);
-	h->obyte = 1;
+	sms_debug(DIR_TX, h);
+	h->framenumber++;	/* Proto 2 */
+	h->obyte = 1;		/* send mark ('1') at the beginning */
 	h->opause = 200;
+	/* Change the initial message delay. BT requires 300ms,
+	 * but for others this might be way too much and the phone
+	 * could time out. XXX make it configurable.
+	 */
 	if (h->omsg[0] == 0x93)
-		h->opause = 2400;	/* initial message delay 300ms (for BT) */
+		h->opause = 200;	/* XXX initial message delay 300ms (for BT) */
 	h->obytep = 0;
 	h->obitp = 0;
+	if (h->protocol == 2) {
+		h->oseizure = 300;      /* Proto 2: 300bits (or more ?) */
+		h->obyte = 0;           /* Seizure starts with  space (0) */
+		h->opause = 400;
+	} else {
+		h->oseizure = 0;        /* Proto 1: No seizure */
+	}
 	/* Note - setting osync triggers the generator */
-	h->osync = 80;			/* 80 sync bits */
+	h->osync = OSYNC_BITS;			/* 80 sync bits */
 	h->obyten = len + 1;		/* bytes to send (including checksum) */
 }
 
@@ -1199,15 +1500,22 @@ static int sms_generate (struct ast_channel *chan, void *data, int len, int samp
 
 		if (h->opause)
 			h->opause--;
-		else if (h->obyten || h->osync) {		/* sending data */
+		else if (h->obyten || h->osync) {	/* sending data */
 			buf[i] = wave_out[h->ophase];
 			h->ophase += (h->obyte & 1) ? 13 : 21;	/* compute next phase */
 			if (h->ophase >= 80)
 				h->ophase -= 80;
 			if ((h->ophasep += 12) >= 80) {		/* time to send the next bit */
 				h->ophasep -= 80;
-				if (h->osync) {
+				if (h->oseizure > 0) {           /* sending channel seizure (proto 2) */
+					h->oseizure--;
+					h->obyte ^= 1;	/* toggle low bit */
+				} else if (h->osync) {
+					h->obyte = 1;	/* send mark as sync bit */
 					h->osync--;		/* sending sync bits */
+					if (h->osync == 0 && h->protocol == 2 && h->omsg[0] == DLL2_SMS_EST) {
+						h->obytep = h->obyten = 0;	/* we are done */
+					}
 				} else {
 					h->obitp++;
 					if (h->obitp == 1)
@@ -1250,8 +1558,13 @@ static int sms_generate (struct ast_channel *chan, void *data, int len, int samp
  */
 static void sms_process (sms_t * h, int samples, signed short *data)
 {
+#if 1
+	/* Do we really need to remain deaf while a packet is
+	 * being transmitted ?
+	 */
 	if (h->obyten || h->osync)
 		return;						 /* sending */
+#endif
 	while (samples--) {
 		unsigned long long m0, m1;
 		if (abs (*data) > h->imag)
@@ -1301,27 +1614,43 @@ static void sms_process (sms_t * h, int samples, signed short *data)
 					h->iphasep = 0;
 				}
 				if (bit && h->ibitc == 200) {						 /* sync, restart message */
+					/* Protocol 2: empty connnection ready (I am master) */
+					if(h->framenumber<0 && h->ibytec>=160 && !memcmp(h->imsg,"UUUUUUUUUUUUUUUUUUUU",20)) {
+						h->framenumber = 1;
+						if (option_verbose > 2)
+							ast_verbose (VERBOSE_PREFIX_3 "SMS protocol 2 detected\n");
+						h->protocol = 2;
+						h->imsg[0] = 0xff;      /* special message (fake) */
+						h->imsg[1] = h->imsg[2] = 0x00;
+						h->ierr = h->ibitn = h->ibytep = h->ibytec = 0;
+						sms_messagerx (h);
+					}
 					h->ierr = h->ibitn = h->ibytep = h->ibytec = 0;
 				}
 				if (h->ibitn) {
 					h->iphasep += 12;
-					if (h->iphasep >= 80) {					 /* next bit */
+					if (h->iphasep >= 80) {			 		/* next bit */
 						h->iphasep -= 80;
-						if (h->ibitn++ == 9) {				 /* end of byte */
-							if (!bit)  /* bad stop bit */
+						if (h->ibitn++ == 9) {		 		/* end of byte */
+							if (!bit) { /* bad stop bit */
+								ast_log(LOG_NOTICE, "bad stop bit");
 								h->ierr = 0xFF; /* unknown error */
-							else {
+							} else {
 								if (h->ibytep < sizeof (h->imsg)) {
 									h->imsg[h->ibytep] = h->ibytev;
 									h->ibytec += h->ibytev;
 									h->ibytep++;
-								} else if (h->ibytep == sizeof (h->imsg))
+								} else if (h->ibytep == sizeof (h->imsg)) {
+									ast_log(LOG_NOTICE, "msg too large");
 									h->ierr = 2; /* bad message length */
+								}
 								if (h->ibytep > 1 && h->ibytep == 3 + h->imsg[1] && !h->ierr) {
 									if (!h->ibytec)
 										sms_messagerx (h);
-									else
+									else {
+										ast_log(LOG_NOTICE, "bad checksum");
 										h->ierr = 1;		/* bad checksum */
+									}
 								}
 							}
 							h->ibitn = 0;
@@ -1332,11 +1661,12 @@ static void sms_process (sms_t * h, int samples, signed short *data)
 			}
 		} else {			 /* lost carrier */
 			if (h->idle++ == 80000) {		 /* nothing happening */
-				ast_log (LOG_EVENT, "No data, hanging up\n");
+				ast_log (LOG_NOTICE, "No data, hanging up\n");
 				h->hangup = 1;
 				h->err = 1;
 			}
 			if (h->ierr) {		/* error */
+				ast_log (LOG_NOTICE, "Error %d, hanging up\n", h->ierr);
 				/* Protocol 1 */
 				h->err = 1;
 				h->omsg[0] = 0x92;  /* error */
@@ -1398,6 +1728,7 @@ static int sms_exec (struct ast_channel *chan, void *data)
 		for (p = (unsigned char *)h.queue; *p; p++)
 			if (!isalnum (*p))
 				*p = '-';			  /* make very safe for filenames */
+ast_log(LOG_NOTICE, "sms to queue %s\n", h.queue);
 		while (*d && *d != '|') {
 			switch (*d) {
 			case 'a':				 /* we have to send the initial FSK sequence */
@@ -1406,6 +1737,9 @@ static int sms_exec (struct ast_channel *chan, void *data)
 			case 's':				 /* we are acting as a service centre talking to a phone */
 				h.smsc = 1;
 				break;
+			case 't':                                /* use protocol 2 ([t]wo)! couldn't use numbers *!* */
+				h.protocol = 2;
+				break;
 				/* the following apply if there is an arg3/4 and apply to the created message file */
 			case 'r':
 				h.srr = 1;
@@ -1462,9 +1796,15 @@ static int sms_exec (struct ast_channel *chan, void *data)
 		}
 
 		if (answer) {
+			h.framenumber = 1;             /* Proto 2 */
 			/* set up SMS_EST initial message */
-			h.omsg[0] = 0x93;
-			h.omsg[1] = 0;
+			if (h.protocol == 2) {
+				h.omsg[0] = DLL2_SMS_EST;
+				h.omsg[1] = 0;
+			} else {
+				h.omsg[0] = DLL1_SMS_EST | DLL1_SMS_COMPLETE;
+				h.omsg[1] = 0;
+			}
 			sms_messagetx (&h);
 		}
 	}