Looking for a smaller (short cord, db9) USB/Serial converter, I just
bought one of these:
http://www.newegg.com/Product/Product.aspx?Item=N82E16812203018
(KINAMAX 1 FT USB to Serial DB9 (9 pin) RS232 Cable Model CB-RS232 - Retail)
though it looks like they actually sent
http://www.newegg.com/Product/Product.aspx?Item=N82E16812156003
(SABRENT SBT-USC1K USB to Serial (9-pin) DB-9 RS-232 Adapter Cable - Retail)
I bought it to use with an Asus Eee running the default Linux OS (2.6.21
based kernel). When plugged in, it's detected as:
[ 7517.340000] usb 2-2: new full speed USB device using uhci_hcd and
address 2
[ 7517.490000] usb 2-2: configuration #1 chosen from 1 choice
[ 7517.580000] drivers/usb/serial/usb-serial.c: USB Serial support
registered for pl2303
[ 7517.580000] pl2303 2-2:1.0: pl2303 converter detected
[ 7517.580000] usb 2-2: pl2303 converter now attached to ttyUSB1
[ 7517.580000] usbcore: registered new interface driver pl2303
[ 7517.580000] drivers/usb/serial/pl2303.c: Prolific PL2303 USB to serial
adaptor driver
In this case, it's ttyUSB1 because I have another adaptor (using the
mct_u232 driver currently plugged in). The problem I'm having is that the
pl2303 based adaptor "comes and goes". Sometimes it will disconnect
immediately after the driver loads. Sometimes it works for a while and
then disconnects. Sometimes it'll reconnect so fast, it'll initially
connect as ttyUSB0, disconnect and reconnect and become ttyUSB1. More
often, after it's disconnected, I have to physically remove and reconnect
it to get it back.
I haven't had this problem with the mct_u232 based device.
I've tested the new one in another system to make sure it's not a problem
with the Eee.
[2.6.17-1.2142_FC4]
Jan 24 13:07:51 solo kernel: usb 1-2.3: new full speed USB device using
ehci_hcd and address 20
Jan 24 13:07:51 solo kernel: usb 1-2.3: configuration #1 chosen from 1
choice
Jan 24 13:07:51 solo kernel: pl2303 1-2.3:1.0: pl2303 converter detected
Jan 24 13:07:51 solo kernel: usb 1-2.3: pl2303 converter now attached to
ttyUSB0
Jan 24 13:08:03 solo kernel: usb 1-2.3: USB disconnect, address 20
Jan 24 13:08:03 solo kernel: pl2303 ttyUSB0: pl2303 converter now
disconnected from ttyUSB0
Jan 24 13:08:03 solo kernel: pl2303 1-2.3:1.0: device disconnected
It's still physically connected during all the messages above. So the
question is, is this a driver problem or bad USB/Serial converter, or one
that just doesn't quite get alonng with the pl2303 driver?
I saw from the list archive that there have been either some issues with
the pl2303 driver or just with buggy hardware in the past, and so I'm
wondering, should I roll the dice with another pl2303 based product or try
to find something else?
Bus 001 Device 028: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial
Port
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 1.10
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x067b Prolific Technology, Inc.
idProduct 0x2303 PL2303 Serial Port
bcdDevice 2.02
iManufacturer 0
iProduct 0
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 39
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xa0
Remote Wakeup
MaxPower 100mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 3
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 0
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x000a 1x 10 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
T: Bus=01 Lev=02 Prnt=02 Port=02 Cnt=02 Dev#= 28 Spd=12 MxCh= 0
D: Ver= 1.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs= 1
P: Vendor=067b ProdID=2303 Rev= 2.02
C:* #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr=100mA
I: If#= 0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=pl2303
E: Ad=81(I) Atr=03(Int.) MxPS= 10 Ivl=1ms
E: Ad=02(O) Atr=02(Bulk) MxPS= 64 Ivl=0ms
E: Ad=83(I) Atr=02(Bulk) MxPS= 64 Ivl=0ms
----------------------------------------------------------------------
Jon Lewis | I route
Senior Network Engineer | therefore you are
Atlantic Net |
_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________
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