diff --git a/include/fifo.h b/include/fifo.h
index 42a90a5..8baf0fa 100644
--- a/include/fifo.h
+++ b/include/fifo.h
@@ -9,7 +9,7 @@ struct fifo {
 
 	uint16_t pdc_tx;
 	uint16_t pdc_rx;
-	
+
 	uint32_t size;
 	char buf[0];
 };
@@ -23,6 +23,8 @@ uint32_t fifo_txpdc(struct fifo *fifo, AT91S_PDC *pdc, uint16_t maxsize);
 uint32_t fifo_putbyte(struct fifo *fifo, char c);
 uint32_t fifo_getbyte(struct fifo *fifo, char *p);
 
+char * fifo_peek(struct fifo *fifo, uint32_t len);
+
 struct fifo * fifo_alloc(uint32_t size);
 
 #endif /*FIFO_H_*/
diff --git a/include/telemetrie.h b/include/telemetrie.h
index 26d07dd..a72a19e 100644
--- a/include/telemetrie.h
+++ b/include/telemetrie.h
@@ -48,7 +48,7 @@ struct tdc_getvars_reply {
 	uint8_t size;
 	uint8_t id;			// variable ID (max 256 vars / board)
 	uint32_t flags;			// variable parameters (type, size, ro/rw)
-	uint8_t name[0];		// variable name, excluding '\0'
+	char name[0];		// variable name, excluding '\0'
 } __attribute__ ((packed));
 
 struct tdc_getvalue_request {
@@ -87,8 +87,8 @@ struct tdc_reqvalues_reply {
 
 
 struct tdc_value {
-	const void *ptr;
-	const uint8_t *name;
+	void *data;
+	const char *name;
 	uint32_t flags;
 };
 
diff --git a/src/fifo.c b/src/fifo.c
index 63a8263..a17584b 100644
--- a/src/fifo.c
+++ b/src/fifo.c
@@ -16,6 +16,7 @@
  *   Free Software Foundation, Inc.,                                       *
  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
  ***************************************************************************/
+#include <stdio.h>
 #include "AT91SAM7S256.h"
 #include "atomic.h"
 #include "fifo.h"
@@ -45,6 +46,7 @@ static uint32_t fifo_used(struct fifo *fifo)
 uint32_t fifo_put(struct fifo *fifo, const char *buf, uint32_t len)
 {
 	uint32_t left = fifo->size - fifo_used(fifo);
+	// TODO: check semantic
 	if (len > left)
 		len = left;
 
@@ -72,6 +74,19 @@ uint32_t fifo_get(struct fifo *fifo, char *buf, uint32_t len)
 	return len;
 }
 
+/*
+ * returns a pointer to the data in the fifo
+ * (without changing internal state)
+ */
+char * fifo_peek(struct fifo *fifo, uint32_t len)
+{
+	uint32_t used = fifo_used(fifo);
+	if (len > used)
+		return NULL;
+
+	return fifo->buf + (fifo->out & FIFO_MASK(fifo));
+}
+
 /*
  * receive data via PDC and put it into fifo
  */
diff --git a/src/telemetrie.c b/src/telemetrie.c
index 5ce39e1..4860673 100644
--- a/src/telemetrie.c
+++ b/src/telemetrie.c
@@ -27,12 +27,18 @@
 extern struct tdc_value _tdc_value_table;
 extern struct tdc_value _tdc_value_table_end;
 
-typedef uint32_t (txfunc_t)(const uint8_t *data, uint32_t size);
+/*
+ * transmit function
+ * returns:
+ * -1 : could not sent data (e.g. fifo full)
+ * >= 0 : bytes sent
+ */
+typedef uint32_t (txfunc_t)(struct tdc_pkt_header *head);
 
 /* just eat the packet */
-static uint32_t txdummy(const uint8_t *data, uint32_t size)
+static uint32_t txdummy(struct tdc_pkt_header *head)
 {
-	return -1;
+	return head->size;
 }
 
 /* table of txfuncs for routing/forwarding */
@@ -53,88 +59,84 @@ void tdc_register_txfunc(uint32_t addr, txfunc_t *txfunc)
 		transmit_table[addr] = txfunc;
 }
 
-int32_t tdc_transmit(uint32_t addr, const uint8_t *data, uint32_t size)
+int32_t tdc_transmit(uint32_t addr, struct tdc_pkt_header *head)
 {
 	if (addr <= ARRAY_SIZE(transmit_table))
-		return transmit_table[addr](data, size);
+		return transmit_table[addr](head);
 
 	return -1;
 }
 
 /*
-void *blub = NULL;
-func(&blub);
-*/
-int32_t tdc_get_vars(void **privdata)
+ * send all variable names & flags
+ * returns:
+ * 0 - success (*id = 0)
+ * -1 - not all data was sent, restart request later (*id has restart-point)
+ */
+int32_t tdc_get_vars(uint32_t *id)
 {
-	struct tdc_value **value = (struct tdc_value **)privdata;
+	struct tdc_value *value = &_tdc_value_table + *id;
 
-	if (*value == NULL)
-		*value = &_tdc_value_table;
-
-	uint32_t id = (*value - &_tdc_value_table) / sizeof(struct tdc_value);
-
-	while (*value < &_tdc_value_table_end) {
-		uint32_t datalen = strlen((*value)->name);
+	while (value < &_tdc_value_table_end) {
+		uint32_t datalen = strlen(value->name);
 
 		struct tdc_getvars_reply *reply = alloc(sizeof(struct tdc_getvars_reply) + datalen);
 		reply->cmd = TDC_REPLY | TDC_ADDR1 | TDC_GETVARS;
 		reply->size = sizeof(struct tdc_getvars_reply) + datalen;
-		reply->id = id;
-		reply->flags = (*value)->flags;
-		memcpy(reply->name, (*value)->name, datalen);
+		reply->id = *id;
+		reply->flags = value->flags;
+		memcpy(reply->name, value->name, datalen);
 
-		int32_t ret = transmit_table[TDC_ADDR0]((const uint8_t *)reply, reply->size);
+		uint32_t txerror = (tdc_transmit(TDC_ADDR0, ((struct tdc_pkt_header *)reply)) != reply->size);
 		free(reply);
 
-		if (ret != reply->size)
+		/* transmit fifo is full, remember position (*id) and restart */
+		if (txerror)
 			return -1;
 
-		id++;
-		(*value)++;
+		(*id)++;
+		value++;
 	}
-
-	/* TODO: all done */
-	(*value) = NULL;
+	*id = 0;
 	return 0;
 }
 
-#if 0
-
-static int32_t tdc_get_values(uint8_t *buf, uint32_t size, void **key)
+int32_t tdc_get_value(uint32_t id)
 {
-	if (*key == NULL)
-		*key = &_tdc_value_table;
+	struct tdc_value *value = &_tdc_value_table + id;
+	uint32_t datalen = value->flags & TDC_SIZEMASK;
 
-	uint32_t id = (*key - &_tdc_value_table) / sizeof(struct tdc_value);
-	uint32_t pos = 0;
+	struct tdc_getvalue_reply *reply = alloc(sizeof(struct tdc_getvalue_reply) + datalen);
+	reply->cmd = TDC_REPLY | TDC_ADDR1 | TDC_GETVALUE;
+	reply->size = sizeof(struct tdc_getvars_reply) + datalen;
+	reply->id = id;
+	memcpy(reply->data, value->data, datalen);
 
-	while (*key < &_tdc_value_table_end) {
-		struct tdc_value *tmp = (struct tdc_value *)*key;
-		uint32_t datalen = (tmp->flags & TDC_SIZEMASK);
+	int32_t txerror = (tdc_transmit(TDC_ADDR0, ((struct tdc_pkt_header *)reply)) != reply->size);
+	free(reply);
 
-		/* fits in buffer? */
-		if ((size - pos) < (2 + 1 + datalen))
-			return (pos > 0) ? pos : -1;
-
-		buf[pos++] = TDC_VALUEOP;
-		buf[pos++] = 1 + datalen;
-		buf[pos++] = id++;
-
-		memcpy(buf + pos, tmp->ptr, datalen);
-		pos += datalen;
-
-		*key += sizeof(struct tdc_value);
-	}
-	return pos;
+	return (txerror) ? -1 : 0;
+}
+
+void tdc_set_value(uint32_t id, uint8_t *data)
+{
+	struct tdc_value *value = &_tdc_value_table + id;
+	uint32_t datalen = value->flags & TDC_SIZEMASK;
+
+	// TODO: atomic?
+	memcpy(value->data, data, datalen);
 }
-#endif
 
 /*
  * parses tdc data
+ * returns:
+ * -1 : data too short / error
+ * >= 0 : data read, come back if there is more
  */
 int32_t tdc_parse_pkt(txfunc_t *txfunc, const uint8_t *data, uint32_t size)
 {
+	// TODO: use a fifo, with a peek function?
+
 	struct tdc_pkt_header *head = (struct tdc_pkt_header *)data;
 
 	if (size < sizeof(struct tdc_pkt_header))
@@ -142,41 +144,55 @@ int32_t tdc_parse_pkt(txfunc_t *txfunc, const uint8_t *data, uint32_t size)
 
 	/* if it's a hello-request, remember the txfunc as path to the host */
 	if ((head->cmd & (TDC_OPCODEMASK & TDC_DIR)) == TDC_HELLO)
-		transmit_table[TDC_ADDR0] = txfunc;
+		tdc_register_txfunc(TDC_ADDR0, txfunc);
 
 	/* all replys go to the HOST */
 	if (head->cmd & TDC_REPLY) {
-		return transmit_table[TDC_ADDR0](data, head->size);
+		// TODO: wrong returncode
+		return tdc_transmit(TDC_ADDR0, head);
 	}
 
 	/* forward this packet? */
 	if ((head->cmd & TDC_ADDRMASK) != TDC_ADDR1) {
 		uint32_t addr = (head->cmd & TDC_ADDRMASK) >> 4;
-		return transmit_table[addr](data, head->size);
+		// TODO: wrong returncode
+		return tdc_transmit(addr, head);
 	}
 
 	/* parse the packet */
 	switch (head->cmd & TDC_OPCODEMASK) {
 	/* HELLO from HOST */
 	case TDC_HELLO:
-		transmit_table[TDC_ADDR0]((const uint8_t *)&hello_reply, sizeof(hello_reply));
+		tdc_transmit(TDC_ADDR0, (struct tdc_pkt_header *)&hello_reply);
 		break;
 
-	case TDC_GETVARS:
-		// TODO: exec func
-		break;
+	case TDC_GETVARS: {
+		static uint32_t i;
 
-	case TDC_GETVALUE:
-		// TODO: exec func
-		break;
+		/* tx-fifo is full, complete request later */
+		if (tdc_get_vars(&i) == -1)
+			return 0;
 
-	case TDC_SETVALUE:
-		// TODO: exec func
-		break;
+	}	break;
 
-	case TDC_REQVALUES:
-		// TODO: exec func
-		break;
+	case TDC_GETVALUE: {
+		struct tdc_getvalue_request *pkt = (struct tdc_getvalue_request *)data;
+
+		/* tx-fifo is full, retry request later */
+		if (tdc_get_value(pkt->id) == -1)
+			return 0;
+
+	}	break;
+
+	case TDC_SETVALUE: {
+		struct tdc_setvalue_request *pkt = (struct tdc_setvalue_request *)data;
+		tdc_set_value(pkt->id, pkt->data);
+	}	break;
+
+	case TDC_REQVALUES: {
+		struct tdc_reqvalues_request *pkt = (struct tdc_reqvalues_request *)data;
+
+	}	break;
 
 	case TDC_TERMINAL:
 		// TODO: not possible?