diff --git a/sys/dev/usb/quirk/usb_quirk.c b/sys/dev/usb/quirk/usb_quirk.c
index ea63cd64c7ac..cdfcce8ff45d 100644
--- a/sys/dev/usb/quirk/usb_quirk.c
+++ b/sys/dev/usb/quirk/usb_quirk.c
@@ -125,6 +125,24 @@ static struct usb_quirk_entry usb_quirks[USB_DEV_QUIRKS_MAX] = {
 	/* MS keyboards do weird things */
 	{USB_QUIRK_ENTRY(USB_VENDOR_MICROSOFT, USB_PRODUCT_MICROSOFT_WLINTELLIMOUSE, 0x0000, 0xFFFF, UQ_MS_LEADING_BYTE, UQ_NONE)},
 	{USB_QUIRK_ENTRY(USB_VENDOR_METAGEEK, USB_PRODUCT_METAGEEK_WISPY24X, 0x0000, 0xFFFF, UQ_KBD_IGNORE, UQ_HID_IGNORE, UQ_NONE)},
+	/* umodem(4) device quirks */
+	{USB_QUIRK_ENTRY(USB_VENDOR_METRICOM, USB_PRODUCT_METRICOM_RICOCHET_GS,
+	    0x100, 0x100, UQ_ASSUME_CM_OVER_DATA)},
+	{USB_QUIRK_ENTRY(USB_VENDOR_SANYO, USB_PRODUCT_SANYO_SCP4900,
+	    0x000, 0x000, UQ_ASSUME_CM_OVER_DATA)},
+	{USB_QUIRK_ENTRY(USB_VENDOR_MOTOROLA2, USB_PRODUCT_MOTOROLA2_T720C,
+	    0x001, 0x001, UQ_ASSUME_CM_OVER_DATA)},
+	{USB_QUIRK_ENTRY(USB_VENDOR_EICON, USB_PRODUCT_EICON_DIVA852,
+	    0x100, 0x100, UQ_ASSUME_CM_OVER_DATA)},
+	{USB_QUIRK_ENTRY(USB_VENDOR_SIEMENS2, USB_PRODUCT_SIEMENS2_ES75,
+	    0x000, 0x000, UQ_ASSUME_CM_OVER_DATA)},
+	{USB_QUIRK_ENTRY(USB_VENDOR_QUALCOMM, USB_PRODUCT_QUALCOMM_CDMA_MSM,
+	    0x0000, 0xFFFF, UQ_ASSUME_CM_OVER_DATA)},
+	{USB_QUIRK_ENTRY(USB_VENDOR_QUALCOMM2, USB_PRODUCT_QUALCOMM2_CDMA_MSM,
+	    0x0000, 0xFFFF, UQ_ASSUME_CM_OVER_DATA)},
+	{USB_QUIRK_ENTRY(USB_VENDOR_CURITEL, USB_PRODUCT_CURITEL_UM175,
+	    0x0000, 0xFFFF, UQ_ASSUME_CM_OVER_DATA)},
+
 };
 
 static const char *usb_quirk_str[USB_QUIRK_MAX] = {
@@ -152,6 +170,7 @@ static const char *usb_quirk_str[USB_QUIRK_MAX] = {
 	[UQ_CFG_INDEX_3]	= "UQ_CFG_INDEX_3",
 	[UQ_CFG_INDEX_4]	= "UQ_CFG_INDEX_4",
 	[UQ_CFG_INDEX_0]	= "UQ_CFG_INDEX_0",
+	[UQ_ASSUME_CM_OVER_DATA]= "UQ_ASSUME_CM_OVER_DATA",
 };
 
 /*------------------------------------------------------------------------*
diff --git a/sys/dev/usb/quirk/usb_quirk.h b/sys/dev/usb/quirk/usb_quirk.h
index f4fb9b9fdc95..ee40c2fb3b93 100644
--- a/sys/dev/usb/quirk/usb_quirk.h
+++ b/sys/dev/usb/quirk/usb_quirk.h
@@ -53,6 +53,7 @@ enum {	/* keep in sync with usb_quirk_str table */
 	UQ_CFG_INDEX_3,		/* select configuration index 3 by default */
 	UQ_CFG_INDEX_4,		/* select configuration index 4 by default */
 	UQ_CFG_INDEX_0,		/* select configuration index 0 by default */
+	UQ_ASSUME_CM_OVER_DATA,	/* modem device breaks on cm over data */
 	USB_QUIRK_MAX
 };
 
diff --git a/sys/dev/usb/serial/umodem.c b/sys/dev/usb/serial/umodem.c
index 6a6d3951a2ba..6945e79e4305 100644
--- a/sys/dev/usb/serial/umodem.c
+++ b/sys/dev/usb/serial/umodem.c
@@ -112,6 +112,7 @@ __FBSDID("$FreeBSD$");
 #define	USB_DEBUG_VAR umodem_debug
 #include <dev/usb/usb_debug.h>
 #include <dev/usb/usb_process.h>
+#include <dev/usb/quirk/usb_quirk.h>
 
 #include <dev/usb/serial/usb_serial.h>
 
@@ -349,16 +350,20 @@ umodem_attach(device_t dev)
 		}
 	}
 
-	if (sc->sc_cm_cap & USB_CDC_CM_OVER_DATA) {
-		if (sc->sc_acm_cap & USB_CDC_ACM_HAS_FEATURE) {
-
-			error = umodem_set_comm_feature
-			    (uaa->device, sc->sc_ctrl_iface_no,
-			    UCDC_ABSTRACT_STATE, UCDC_DATA_MULTIPLEXED);
-
-			/* ignore any errors */
-		}
+	if (usb_test_quirk(uaa, UQ_ASSUME_CM_OVER_DATA)) {
 		sc->sc_cm_over_data = 1;
+	} else {
+		if (sc->sc_cm_cap & USB_CDC_CM_OVER_DATA) {
+			if (sc->sc_acm_cap & USB_CDC_ACM_HAS_FEATURE) {
+
+				error = umodem_set_comm_feature
+				(uaa->device, sc->sc_ctrl_iface_no,
+				 UCDC_ABSTRACT_STATE, UCDC_DATA_MULTIPLEXED);
+
+				/* ignore any errors */
+			}
+			sc->sc_cm_over_data = 1;
+		}
 	}
 	error = usbd_transfer_setup(uaa->device,
 	    sc->sc_iface_index, sc->sc_xfer,
diff --git a/sys/dev/usb/usbdevs b/sys/dev/usb/usbdevs
index 6bec7c737875..9f682147ddf7 100644
--- a/sys/dev/usb/usbdevs
+++ b/sys/dev/usb/usbdevs
@@ -1213,6 +1213,9 @@ product DRESDENELEKTRONIK WIRELESSHANDHELDTERMINAL  0x0004 Wireless Handheld Ter
 /* Dynastream Innovations */
 product DYNASTREAM ANTDEVBOARD	0x1003	ANT dev board
 
+/* Eicon Networks */
+product EICON DIVA852		0x4905	Diva 852 ISDN TA
+
 /* EIZO products */
 product EIZO HUB		0x0000	hub
 product EIZO MONITOR		0x0001	monitor
@@ -1827,6 +1830,7 @@ product MOSCHIP MCS7830		0x7830	MCS7830 Ethernet
 /* Motorola products */
 product MOTOROLA MC141555	0x1555	MC141555 hub controller
 product MOTOROLA SB4100		0x4100	SB4100 USB Cable Modem
+product MOTOROLA2 T720C		0x2822	T720c
 product MOTOROLA2 A41XV32X	0x2a22	A41x/V32x Mobile Phones
 product MOTOROLA2 E398		0x4810	E398 Mobile Phone
 product MOTOROLA2 USBLAN	0x600c	USBLAN