diff --git a/conf/firmwares/subsystems/fixedwing/telemetry_superbitrf.makefile b/conf/firmwares/subsystems/fixedwing/telemetry_superbitrf.makefile
index 6018d66b928..5a7a9d9678d 100644
--- a/conf/firmwares/subsystems/fixedwing/telemetry_superbitrf.makefile
+++ b/conf/firmwares/subsystems/fixedwing/telemetry_superbitrf.makefile
@@ -2,12 +2,12 @@
 # The superbitRF module as telemetry downlink/uplink
 #
 #
-ap.CFLAGS += -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_FBW_DEVICE=superbitrf -DDOWNLINK_AP_DEVICE=superbitrf
-ap.CFLAGS += -DDOWNLINK_TRANSPORT=pprz_tp -DDATALINK=SUPERBITRF
-#ap.CFLAGS += -DUSE_SUPERBITRF -DUSE_SPI2 -DUSE_SPI_SLAVE2
 
-ap.srcs += peripherals/cyrf6936.c
-ap.srcs += subsystems/datalink/downlink.c subsystems/datalink/superbitrf.c subsystems/datalink/pprz_transport.c subsystems/datalink/telemetry.c
+# include shared part for ap
+ifeq ($(TARGET),ap)
+include $(CFG_SHARED)/telemetry_superbitrf.makefile
+endif
+
 ap.srcs += $(SRC_FIRMWARE)/datalink.c $(SRC_FIRMWARE)/ap_downlink.c
 
 # avoid fbw_telemetry_mode error
diff --git a/conf/firmwares/subsystems/fixedwing/telemetry_transparent.makefile b/conf/firmwares/subsystems/fixedwing/telemetry_transparent.makefile
index 8f4fa0a48e2..52d2e09b334 100644
--- a/conf/firmwares/subsystems/fixedwing/telemetry_transparent.makefile
+++ b/conf/firmwares/subsystems/fixedwing/telemetry_transparent.makefile
@@ -1,15 +1,11 @@
 # Hey Emacs, this is a -*- makefile -*-
 
-PPRZ_MODEM_PORT_LOWER=$(shell echo $(MODEM_PORT) | tr A-Z a-z)
+# include shared part for ap
+ifeq ($(TARGET),ap)
+include $(CFG_SHARED)/telemetry_transparent.makefile
+endif
 
-telemetry_CFLAGS = -DUSE_$(MODEM_PORT)
-telemetry_CFLAGS += -D$(MODEM_PORT)_BAUD=$(MODEM_BAUD)
-telemetry_CFLAGS += -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_DEVICE=$(PPRZ_MODEM_PORT_LOWER) -DPPRZ_UART=$(PPRZ_MODEM_PORT_LOWER)
-telemetry_CFLAGS += -DDOWNLINK_TRANSPORT=pprz_tp -DDATALINK=PPRZ
-telemetry_srcs = subsystems/datalink/downlink.c subsystems/datalink/pprz_transport.c subsystems/datalink/telemetry.c
-
-ap.CFLAGS += $(telemetry_CFLAGS)
-ap.srcs += $(telemetry_srcs) $(SRC_FIRMWARE)/datalink.c $(SRC_FIRMWARE)/ap_downlink.c
+ap.srcs += $(SRC_FIRMWARE)/datalink.c $(SRC_FIRMWARE)/ap_downlink.c
 
 # avoid fbw_telemetry_mode error
 ap.srcs += $(SRC_FIRMWARE)/fbw_downlink.c
diff --git a/conf/firmwares/subsystems/fixedwing/telemetry_transparent_usb.makefile b/conf/firmwares/subsystems/fixedwing/telemetry_transparent_usb.makefile
index 88c315f87d7..797f16a1f87 100644
--- a/conf/firmwares/subsystems/fixedwing/telemetry_transparent_usb.makefile
+++ b/conf/firmwares/subsystems/fixedwing/telemetry_transparent_usb.makefile
@@ -2,28 +2,13 @@
 
 #serial USB (e.g. /dev/ttyACM0)
 
-telemetry_CFLAGS = -DDOWNLINK -DDOWNLINK_DEVICE=usb_serial -DPPRZ_UART=usb_serial
-telemetry_CFLAGS += -DDOWNLINK_TRANSPORT=pprz_tp -DDATALINK=PPRZ -DUSE_USB_SERIAL
-telemetry_srcs = subsystems/datalink/downlink.c subsystems/datalink/pprz_transport.c subsystems/datalink/telemetry.c
-telemetry_srcs += $(SRC_FIRMWARE)/datalink.c $(SRC_FIRMWARE)/ap_downlink.c $(SRC_FIRMWARE)/fbw_downlink.c
-# avoid fbw_telemetry_mode error
-telemetry_srcs += $(SRC_FIRMWARE)/fbw_downlink.c
+ifeq ($(TARGET), ap)
+include $(CFG_SHARED)/telemetry_transparent_usb.makefile
+endif
 
-ap.CFLAGS += $(telemetry_CFLAGS)
-ap.srcs += $(telemetry_srcs)
+ap.srcs += $(SRC_FIRMWARE)/datalink.c $(SRC_FIRMWARE)/ap_downlink.c $(SRC_FIRMWARE)/fbw_downlink.c
+# avoid fbw_telemetry_mode error
+ap.srcs += $(SRC_FIRMWARE)/fbw_downlink.c
 
 fbw.srcs += $(SRC_FIRMWARE)/fbw_downlink.c
 
-ifeq ($(ARCH), lpc21)
-ap.CFLAGS += -DUSE_USB_HIGH_PCLK
-ap.srcs += $(SRC_ARCH)/usb_ser_hw.c $(SRC_ARCH)/lpcusb/usbhw_lpc.c $(SRC_ARCH)/lpcusb/usbcontrol.c
-ap.srcs += $(SRC_ARCH)/lpcusb/usbstdreq.c $(SRC_ARCH)/lpcusb/usbinit.c
-else
-ifeq ($(ARCH), stm32)
-ap.srcs += $(SRC_ARCH)/usb_ser_hw.c
-else
-ifneq ($(ARCH), sim)
-$(error telemetry_transparent_usb currently only implemented for the lpc21 and stm32)
-endif
-endif
-endif
diff --git a/conf/firmwares/subsystems/fixedwing/telemetry_w5100.makefile b/conf/firmwares/subsystems/fixedwing/telemetry_w5100.makefile
index 59408909d47..eb949fe7bd6 100644
--- a/conf/firmwares/subsystems/fixedwing/telemetry_w5100.makefile
+++ b/conf/firmwares/subsystems/fixedwing/telemetry_w5100.makefile
@@ -2,36 +2,13 @@
 
 # W5100 ethernet chip.
 
-W5100_IP ?= "192,168,25,47"
-W5100_SUBNET ?= "255,255,255,0"
-W5100_MULTICAST_IP ?= "224,1,1,11"
-W5100_MULTICAST_PORT ?= "1234"
+ifeq ($(TARGET), ap)
+include $(CFG_SHARED)/telemetry_w5100.makefile
+endif
 
-ap.CFLAGS += -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_DEVICE=chip0
-ap.CFLAGS += -DDOWNLINK_TRANSPORT=pprz_tp -DDATALINK=W5100
-ap.CFLAGS += -DW5100_IP=$(W5100_IP) -DW5100_SUBNET=$(W5100_SUBNET) -DW5100_MULTICAST_IP=$(W5100_MULTICAST_IP) -DW5100_MULTICAST_PORT=$(W5100_MULTICAST_PORT)
-ap.srcs += subsystems/datalink/downlink.c subsystems/datalink/w5100.c subsystems/datalink/pprz_transport.c subsystems/datalink/telemetry.c
 ap.srcs += $(SRC_FIRMWARE)/datalink.c $(SRC_FIRMWARE)/ap_downlink.c
 
 # avoid fbw_telemetry_mode error
 ap.srcs += $(SRC_FIRMWARE)/fbw_downlink.c
 
 fbw.srcs += $(SRC_FIRMWARE)/fbw_downlink.c
-
-ifeq ($(ARCH), lpc21)
-# only an issue of setting the DRDY pin in w5100.c, which is stm32 specific
-$(error Not implemented for the LCP21x yet.)
-ap.CFLAGS += -DUSE_SPI1
-# default SPI device for W5100 is already SPI1
-ap.CFLAGS += -DUSE_SPI_SLAVE0
-ap.CFLAGS += -DW5100_SLAVE_IDX=0
-else ifeq ($(ARCH), stm32)
-# on extra SPI1 connector
-ap.CFLAGS += -DUSE_SPI1
-# default SPI device for W5100 is already SPI1
-# Slave select configuration
-# SLAVE1 is SS on external SPI1 connector (PA04)
-ap.CFLAGS += -DUSE_SPI_SLAVE1
-# default slave select for W5100 is already SLAVE1
-#ap.CFLAGS += -DW5100_SLAVE_IDX=1
-endif
diff --git a/conf/firmwares/subsystems/fixedwing/telemetry_xbee_api.makefile b/conf/firmwares/subsystems/fixedwing/telemetry_xbee_api.makefile
index e0cd6781427..b5efeeffd12 100644
--- a/conf/firmwares/subsystems/fixedwing/telemetry_xbee_api.makefile
+++ b/conf/firmwares/subsystems/fixedwing/telemetry_xbee_api.makefile
@@ -2,14 +2,11 @@
 
 # XBee modems in API mode
 
-XBEE_MODEM_PORT_LOWER=$(shell echo $(MODEM_PORT) | tr A-Z a-z)
+# include shared part for ap
+ifeq ($(TARGET),ap)
+include $(CFG_SHARED)/telemetry_xbee_api.makefile
+endif
 
-ap.CFLAGS += -DUSE_$(MODEM_PORT)
-ap.CFLAGS += -D$(MODEM_PORT)_BAUD=$(MODEM_BAUD) -DXBEE_BAUD=$(MODEM_BAUD)
-
-ap.CFLAGS += -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_DEVICE=$(XBEE_MODEM_PORT_LOWER) -DXBEE_UART=$(XBEE_MODEM_PORT_LOWER)
-ap.CFLAGS += -DDOWNLINK_TRANSPORT=xbee_tp -DDATALINK=XBEE
-ap.srcs += subsystems/datalink/downlink.c subsystems/datalink/xbee.c subsystems/datalink/telemetry.c
 ap.srcs += $(SRC_FIRMWARE)/datalink.c $(SRC_FIRMWARE)/ap_downlink.c
 
 # avoid fbw_telemetry_mode error
diff --git a/conf/firmwares/subsystems/rotorcraft/fdm_jsbsim.makefile b/conf/firmwares/subsystems/rotorcraft/fdm_jsbsim.makefile
index 4c16104bc95..2551e244ddf 100644
--- a/conf/firmwares/subsystems/rotorcraft/fdm_jsbsim.makefile
+++ b/conf/firmwares/subsystems/rotorcraft/fdm_jsbsim.makefile
@@ -65,8 +65,6 @@ nps.srcs += $(NPSDIR)/nps_main.c                 \
 # for geo mag calculation
 nps.srcs += math/pprz_geodetic_wmm2010.c
 
-nps.CFLAGS += -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_TRANSPORT=ivy_tp -DDOWNLINK_DEVICE=ivy_tp
-nps.srcs += subsystems/datalink/ivy_transport.c
-nps.srcs += subsystems/datalink/downlink.c subsystems/datalink/telemetry.c
+include $(CFG_SHARED)/telemetry_ivy.makefile
 nps.srcs += $(SRC_FIRMWARE)/rotorcraft_telemetry.c
 nps.srcs += $(SRC_FIRMWARE)/datalink.c
diff --git a/conf/firmwares/subsystems/rotorcraft/telemetry_superbitrf.makefile b/conf/firmwares/subsystems/rotorcraft/telemetry_superbitrf.makefile
index 995472343d8..294bd0a08e1 100644
--- a/conf/firmwares/subsystems/rotorcraft/telemetry_superbitrf.makefile
+++ b/conf/firmwares/subsystems/rotorcraft/telemetry_superbitrf.makefile
@@ -1,11 +1,11 @@
 #
 # The superbitRF module as telemetry downlink/uplink
 #
-#
-ap.CFLAGS += -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_DEVICE=superbitrf
-ap.CFLAGS += -DDOWNLINK_TRANSPORT=pprz_tp -DDATALINK=SUPERBITRF
-#ap.CFLAGS += -DUSE_SUPERBITRF -DUSE_SPI2 -DUSE_SPI_SLAVE2
 
-ap.srcs += peripherals/cyrf6936.c
-ap.srcs += subsystems/datalink/downlink.c subsystems/datalink/superbitrf.c subsystems/datalink/pprz_transport.c subsystems/datalink/telemetry.c
+# include generic part
+ifeq ($(TARGET), ap)
+include $(CFG_SHARED)/telemetry_superbitrf.makefile
+endif
+
+# add rotorcraft specific files
 ap.srcs += $(SRC_FIRMWARE)/datalink.c $(SRC_FIRMWARE)/rotorcraft_telemetry.c
diff --git a/conf/firmwares/subsystems/rotorcraft/telemetry_transparent.makefile b/conf/firmwares/subsystems/rotorcraft/telemetry_transparent.makefile
index 760c9b8ce13..e10be4b5ac8 100644
--- a/conf/firmwares/subsystems/rotorcraft/telemetry_transparent.makefile
+++ b/conf/firmwares/subsystems/rotorcraft/telemetry_transparent.makefile
@@ -5,12 +5,8 @@
 # MODEM_BAUD
 #
 
-PPRZ_MODEM_PORT_LOWER=$(shell echo $(MODEM_PORT) | tr A-Z a-z)
+ifeq ($(TARGET), ap)
+include $(CFG_SHARED)/telemetry_transparent.makefile
+endif
 
-ap.CFLAGS += -DUSE_$(MODEM_PORT)
-ap.CFLAGS += -D$(MODEM_PORT)_BAUD=$(MODEM_BAUD)
-
-ap.CFLAGS += -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_DEVICE=$(PPRZ_MODEM_PORT_LOWER) -DPPRZ_UART=$(PPRZ_MODEM_PORT_LOWER)
-ap.CFLAGS += -DDOWNLINK_TRANSPORT=pprz_tp -DDATALINK=PPRZ
-ap.srcs += subsystems/datalink/downlink.c subsystems/datalink/pprz_transport.c subsystems/datalink/telemetry.c
 ap.srcs += $(SRC_FIRMWARE)/datalink.c $(SRC_FIRMWARE)/rotorcraft_telemetry.c
diff --git a/conf/firmwares/subsystems/rotorcraft/telemetry_transparent_udp.makefile b/conf/firmwares/subsystems/rotorcraft/telemetry_transparent_udp.makefile
index d45a02e62dc..80c56f35203 100644
--- a/conf/firmwares/subsystems/rotorcraft/telemetry_transparent_udp.makefile
+++ b/conf/firmwares/subsystems/rotorcraft/telemetry_transparent_udp.makefile
@@ -1,23 +1,8 @@
 
 #serial UDP
 
-include $(CFG_SHARED)/udp.makefile
+ifeq ($(TARGET), ap)
+include $(CFG_SHARED)/telemetry_transparent_udp.makefile
+endif
 
-MODEM_DEV         ?= UDP0
-MODEM_PORT_OUT    ?= 4242
-MODEM_PORT_IN     ?= 4243
-MODEM_BROADCAST   ?= TRUE
-
-UDP_MODEM_PORT_LOWER=$(shell echo $(MODEM_DEV) | tr A-Z a-z)
-
-
-MODEM_CFLAGS  = -DUSE_$(MODEM_DEV) -D$(MODEM_DEV)_PORT_OUT=$(MODEM_PORT_OUT) -D$(MODEM_DEV)_PORT_IN=$(MODEM_PORT_IN)
-MODEM_CFLAGS += -D$(MODEM_DEV)_BROADCAST=$(MODEM_BROADCAST) -D$(MODEM_DEV)_HOST=\"$(MODEM_HOST)\"
-
-TELEM_CFLAGS  = -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_DEVICE=$(UDP_MODEM_PORT_LOWER) -DPPRZ_UART=$(UDP_MODEM_PORT_LOWER)
-TELEM_CFLAGS += -DDOWNLINK_TRANSPORT=pprz_tp -DDATALINK=PPRZ
-
-
-ap.CFLAGS += $(MODEM_CFLAGS) $(TELEM_CFLAGS)
-ap.srcs += subsystems/datalink/downlink.c subsystems/datalink/pprz_transport.c subsystems/datalink/telemetry.c
 ap.srcs += $(SRC_FIRMWARE)/datalink.c $(SRC_FIRMWARE)/rotorcraft_telemetry.c
diff --git a/conf/firmwares/subsystems/rotorcraft/telemetry_transparent_usb.makefile b/conf/firmwares/subsystems/rotorcraft/telemetry_transparent_usb.makefile
index 018de29dfb5..07d75baabb2 100644
--- a/conf/firmwares/subsystems/rotorcraft/telemetry_transparent_usb.makefile
+++ b/conf/firmwares/subsystems/rotorcraft/telemetry_transparent_usb.makefile
@@ -1,23 +1,8 @@
 
 #serial USB (e.g. /dev/ttyACM0)
 
-ifeq ($(ARCH), lpc21)
-ap.CFLAGS += -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_DEVICE=usb_serial -DPPRZ_UART=usb_serial
-ap.CFLAGS += -DDOWNLINK_TRANSPORT=pprz_tp -DDATALINK=PPRZ -DUSE_USB_SERIAL
-ap.srcs += subsystems/datalink/downlink.c subsystems/datalink/pprz_transport.c subsystems/datalink/telemetry.c
-ap.srcs += $(SRC_FIRMWARE)/datalink.c $(SRC_FIRMWARE)/rotorcraft_telemetry.c
-ap.srcs += $(SRC_ARCH)/usb_ser_hw.c $(SRC_ARCH)/lpcusb/usbhw_lpc.c $(SRC_ARCH)/lpcusb/usbcontrol.c
-ap.srcs += $(SRC_ARCH)/lpcusb/usbstdreq.c $(SRC_ARCH)/lpcusb/usbinit.c
-else
-ifeq ($(ARCH), stm32)
-ap.CFLAGS += -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_DEVICE=usb_serial -DPPRZ_UART=usb_serial
-ap.CFLAGS += -DDOWNLINK_TRANSPORT=pprz_tp -DDATALINK=PPRZ -DUSE_USB_SERIAL
-ap.srcs += subsystems/datalink/downlink.c subsystems/datalink/pprz_transport.c subsystems/datalink/telemetry.c
-ap.srcs += $(SRC_FIRMWARE)/datalink.c $(SRC_FIRMWARE)/rotorcraft_telemetry.c
-ap.srcs += $(SRC_ARCH)/usb_ser_hw.c
-else
-ifneq ($(ARCH), sim)
-$(error telemetry_transparent_usb currently only implemented for the lpc21 and stm32)
-endif
-endif
+ifeq ($(TARGET), ap)
+include $(CFG_SHARED)/telemetry_transparent_usb.makefile
 endif
+
+ap.srcs += $(SRC_FIRMWARE)/datalink.c $(SRC_FIRMWARE)/rotorcraft_telemetry.c
diff --git a/conf/firmwares/subsystems/rotorcraft/telemetry_udp.makefile b/conf/firmwares/subsystems/rotorcraft/telemetry_udp.makefile
deleted file mode 100644
index 1e813fc4429..00000000000
--- a/conf/firmwares/subsystems/rotorcraft/telemetry_udp.makefile
+++ /dev/null
@@ -1 +0,0 @@
-$(error The telemetry_udp subsystem has been renamed, please replace <subsystem name="telemetry" type="udp"/> with <subsystem name="telemetry" type="transparent_udp"/> in your airframe file.)
diff --git a/conf/firmwares/subsystems/rotorcraft/telemetry_xbee_api.makefile b/conf/firmwares/subsystems/rotorcraft/telemetry_xbee_api.makefile
index 62dfb06615e..d0ccc027491 100644
--- a/conf/firmwares/subsystems/rotorcraft/telemetry_xbee_api.makefile
+++ b/conf/firmwares/subsystems/rotorcraft/telemetry_xbee_api.makefile
@@ -6,12 +6,8 @@
 # MODEM_BAUD
 #
 
-XBEE_MODEM_PORT_LOWER=$(shell echo $(MODEM_PORT) | tr A-Z a-z)
+ifeq ($(TARGET), ap)
+include $(CFG_SHARED)/telemetry_xbee_api.makefile
+endif
 
-ap.CFLAGS += -DUSE_$(MODEM_PORT)
-ap.CFLAGS += -D$(MODEM_PORT)_BAUD=$(MODEM_BAUD) -DXBEE_BAUD=$(MODEM_BAUD)
-
-ap.CFLAGS += -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_DEVICE=$(XBEE_MODEM_PORT_LOWER) -DXBEE_UART=$(XBEE_MODEM_PORT_LOWER)
-ap.CFLAGS += -DDOWNLINK_TRANSPORT=xbee_tp -DDATALINK=XBEE
-ap.srcs += subsystems/datalink/downlink.c subsystems/datalink/xbee.c subsystems/datalink/telemetry.c
 ap.srcs += $(SRC_FIRMWARE)/datalink.c $(SRC_FIRMWARE)/rotorcraft_telemetry.c
diff --git a/conf/firmwares/subsystems/shared/telemetry_ivy.makefile b/conf/firmwares/subsystems/shared/telemetry_ivy.makefile
new file mode 100644
index 00000000000..c8c0dc86008
--- /dev/null
+++ b/conf/firmwares/subsystems/shared/telemetry_ivy.makefile
@@ -0,0 +1,3 @@
+$(TARGET).CFLAGS += -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_TRANSPORT=ivy_tp -DDOWNLINK_DEVICE=ivy_tp
+$(TARGET).srcs += subsystems/datalink/ivy_transport.c
+$(TARGET).srcs += subsystems/datalink/downlink.c subsystems/datalink/telemetry.c
diff --git a/conf/firmwares/subsystems/shared/telemetry_superbitrf.makefile b/conf/firmwares/subsystems/shared/telemetry_superbitrf.makefile
new file mode 100644
index 00000000000..fce4da75ad2
--- /dev/null
+++ b/conf/firmwares/subsystems/shared/telemetry_superbitrf.makefile
@@ -0,0 +1,10 @@
+#
+# The superbitRF module as telemetry downlink/uplink
+#
+#
+
+$(TARGET).CFLAGS += -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_DEVICE=superbitrf
+$(TARGET).CFLAGS += -DDOWNLINK_TRANSPORT=pprz_tp -DDATALINK=SUPERBITRF
+
+$(TARGET).srcs += peripherals/cyrf6936.c
+$(TARGET).srcs += subsystems/datalink/downlink.c subsystems/datalink/superbitrf.c subsystems/datalink/pprz_transport.c subsystems/datalink/telemetry.c
diff --git a/conf/firmwares/subsystems/shared/telemetry_transparent.makefile b/conf/firmwares/subsystems/shared/telemetry_transparent.makefile
new file mode 100644
index 00000000000..6401eb7ba33
--- /dev/null
+++ b/conf/firmwares/subsystems/shared/telemetry_transparent.makefile
@@ -0,0 +1,16 @@
+#
+# Expected from board file or overriden as xml param :
+#
+# MODEM_PORT
+# MODEM_BAUD
+#
+
+PPRZ_MODEM_PORT_LOWER=$(shell echo $(MODEM_PORT) | tr A-Z a-z)
+
+$(TARGET).CFLAGS += -DUSE_$(MODEM_PORT)
+$(TARGET).CFLAGS += -D$(MODEM_PORT)_BAUD=$(MODEM_BAUD)
+
+$(TARGET).CFLAGS += -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_DEVICE=$(PPRZ_MODEM_PORT_LOWER) -DPPRZ_UART=$(PPRZ_MODEM_PORT_LOWER)
+$(TARGET).CFLAGS += -DDOWNLINK_TRANSPORT=pprz_tp -DDATALINK=PPRZ
+$(TARGET).srcs += subsystems/datalink/downlink.c subsystems/datalink/pprz_transport.c subsystems/datalink/telemetry.c
+
diff --git a/conf/firmwares/subsystems/shared/telemetry_transparent_udp.makefile b/conf/firmwares/subsystems/shared/telemetry_transparent_udp.makefile
new file mode 100644
index 00000000000..93d1b8abce1
--- /dev/null
+++ b/conf/firmwares/subsystems/shared/telemetry_transparent_udp.makefile
@@ -0,0 +1,23 @@
+
+#serial UDP
+
+include $(CFG_SHARED)/udp.makefile
+
+MODEM_DEV         ?= UDP0
+MODEM_PORT_OUT    ?= 4242
+MODEM_PORT_IN     ?= 4243
+MODEM_BROADCAST   ?= TRUE
+
+UDP_MODEM_PORT_LOWER=$(shell echo $(MODEM_DEV) | tr A-Z a-z)
+
+
+MODEM_CFLAGS  = -DUSE_$(MODEM_DEV) -D$(MODEM_DEV)_PORT_OUT=$(MODEM_PORT_OUT) -D$(MODEM_DEV)_PORT_IN=$(MODEM_PORT_IN)
+MODEM_CFLAGS += -D$(MODEM_DEV)_BROADCAST=$(MODEM_BROADCAST) -D$(MODEM_DEV)_HOST=\"$(MODEM_HOST)\"
+
+TELEM_CFLAGS  = -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_DEVICE=$(UDP_MODEM_PORT_LOWER) -DPPRZ_UART=$(UDP_MODEM_PORT_LOWER)
+TELEM_CFLAGS += -DDOWNLINK_TRANSPORT=pprz_tp -DDATALINK=PPRZ
+
+
+$(TARGET).CFLAGS += $(MODEM_CFLAGS) $(TELEM_CFLAGS)
+$(TARGET).srcs += subsystems/datalink/downlink.c subsystems/datalink/pprz_transport.c subsystems/datalink/telemetry.c
+
diff --git a/conf/firmwares/subsystems/shared/telemetry_transparent_usb.makefile b/conf/firmwares/subsystems/shared/telemetry_transparent_usb.makefile
new file mode 100644
index 00000000000..67ab9fab7be
--- /dev/null
+++ b/conf/firmwares/subsystems/shared/telemetry_transparent_usb.makefile
@@ -0,0 +1,19 @@
+
+#serial USB (e.g. /dev/ttyACM0)
+
+$(TARGET).CFLAGS += -DDOWNLINK -DDOWNLINK_DEVICE=usb_serial -DPPRZ_UART=usb_serial
+$(TARGET).CFLAGS += -DDOWNLINK_TRANSPORT=pprz_tp -DDATALINK=PPRZ -DUSE_USB_SERIAL
+$(TARGET).srcs += subsystems/datalink/downlink.c subsystems/datalink/pprz_transport.c subsystems/datalink/telemetry.c
+
+ifeq ($(ARCH), lpc21)
+$(TARGET).srcs += $(SRC_ARCH)/usb_ser_hw.c $(SRC_ARCH)/lpcusb/usbhw_lpc.c $(SRC_ARCH)/lpcusb/usbcontrol.c
+$(TARGET).srcs += $(SRC_ARCH)/lpcusb/usbstdreq.c $(SRC_ARCH)/lpcusb/usbinit.c
+else
+ifeq ($(ARCH), stm32)
+$(TARGET).srcs += $(SRC_ARCH)/usb_ser_hw.c
+else
+ifneq ($(ARCH), sim)
+$(error telemetry_transparent_usb currently only implemented for the lpc21 and stm32)
+endif
+endif
+endif
diff --git a/conf/firmwares/subsystems/shared/telemetry_w5100.makefile b/conf/firmwares/subsystems/shared/telemetry_w5100.makefile
new file mode 100644
index 00000000000..59901cba917
--- /dev/null
+++ b/conf/firmwares/subsystems/shared/telemetry_w5100.makefile
@@ -0,0 +1,31 @@
+# Hey Emacs, this is a -*- makefile -*-
+
+# W5100 ethernet chip.
+
+W5100_IP ?= "192,168,25,47"
+W5100_SUBNET ?= "255,255,255,0"
+W5100_MULTICAST_IP ?= "224,1,1,11"
+W5100_MULTICAST_PORT ?= "1234"
+
+$(TARGET).CFLAGS += -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_DEVICE=chip0
+$(TARGET).CFLAGS += -DDOWNLINK_TRANSPORT=pprz_tp -DDATALINK=W5100
+$(TARGET).CFLAGS += -DW5100_IP=$(W5100_IP) -DW5100_SUBNET=$(W5100_SUBNET) -DW5100_MULTICAST_IP=$(W5100_MULTICAST_IP) -DW5100_MULTICAST_PORT=$(W5100_MULTICAST_PORT)
+$(TARGET).srcs += subsystems/datalink/downlink.c subsystems/datalink/w5100.c subsystems/datalink/pprz_transport.c subsystems/datalink/telemetry.c
+
+ifeq ($(ARCH), lpc21)
+# only an issue of setting the DRDY pin in w5100.c, which is stm32 specific
+$(error Not implemented for the LCP21x yet.)
+$(TARGET).CFLAGS += -DUSE_SPI1
+# default SPI device for W5100 is already SPI1
+$(TARGET).CFLAGS += -DUSE_SPI_SLAVE0
+$(TARGET).CFLAGS += -DW5100_SLAVE_IDX=0
+else ifeq ($(ARCH), stm32)
+# on extra SPI1 connector
+$(TARGET).CFLAGS += -DUSE_SPI1
+# default SPI device for W5100 is already SPI1
+# Slave select configuration
+# SLAVE1 is SS on external SPI1 connector (PA04)
+$(TARGET).CFLAGS += -DUSE_SPI_SLAVE1
+# default slave select for W5100 is already SLAVE1
+#$(TARGET).CFLAGS += -DW5100_SLAVE_IDX=1
+endif
diff --git a/conf/firmwares/subsystems/shared/telemetry_xbee_api.makefile b/conf/firmwares/subsystems/shared/telemetry_xbee_api.makefile
new file mode 100644
index 00000000000..f0b0b0b9842
--- /dev/null
+++ b/conf/firmwares/subsystems/shared/telemetry_xbee_api.makefile
@@ -0,0 +1,16 @@
+# XBee modems in API mode
+#
+# Expected from board file or overriden as xml param :
+#
+# MODEM_PORT
+# MODEM_BAUD
+#
+
+XBEE_MODEM_PORT_LOWER=$(shell echo $(MODEM_PORT) | tr A-Z a-z)
+
+$(TARGET).CFLAGS += -DUSE_$(MODEM_PORT)
+$(TARGET).CFLAGS += -D$(MODEM_PORT)_BAUD=$(MODEM_BAUD) -DXBEE_BAUD=$(MODEM_BAUD)
+
+$(TARGET).CFLAGS += -DDOWNLINK -DPERIODIC_TELEMETRY -DDOWNLINK_DEVICE=$(XBEE_MODEM_PORT_LOWER) -DXBEE_UART=$(XBEE_MODEM_PORT_LOWER)
+$(TARGET).CFLAGS += -DDOWNLINK_TRANSPORT=xbee_tp -DDATALINK=XBEE
+$(TARGET).srcs += subsystems/datalink/downlink.c subsystems/datalink/xbee.c subsystems/datalink/telemetry.c
diff --git a/sw/airborne/subsystems/datalink/downlink.h b/sw/airborne/subsystems/datalink/downlink.h
index 816725db8e5..d0970fcd793 100644
--- a/sw/airborne/subsystems/datalink/downlink.h
+++ b/sw/airborne/subsystems/datalink/downlink.h
@@ -76,12 +76,6 @@
 #define DefaultChannel DOWNLINK_TRANSPORT
 #endif
 
-// FIXME are DOWNLINK_AP|FBW_DEVICE distinction really necessary ?
-// by default use AP_DEVICE if nothing is set ?
-#ifndef DOWNLINK_DEVICE
-#define DOWNLINK_DEVICE DOWNLINK_AP_DEVICE
-#endif
-
 #ifndef DefaultDevice
 #define DefaultDevice DOWNLINK_DEVICE
 #endif