Re: How to use an USB<->serial adapter?

From: Daniel Egger
Date: Mon Aug 25 2003 - 05:28:51 EST


Am Mon, 2003-08-25 um 08.24 schrieb Boszormenyi Zoltan:

> What product is this? Mine is a Wiretek UN8BE, based on Prolific 2303.

Mine is from STLAB.

Bus 002 Device 003: ID 7b06:0323
Language IDs: none (invalid length string descriptor 63; len=7)
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 10.01
bDeviceClass 0 Interface
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x7b06
idProduct 0x0323
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
wMaxPacketSize 10
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type none
wMaxPacketSize 64
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 2
Transfer Type Bulk
Synch Type none
wMaxPacketSize 64
bInterval 0
Language IDs: none (invalid length string descriptor 63; len=7)

Hrm, lsusb seems to have an endianess problem, the vendorid is garbled.

> In the shop they said this one cannot be used as a null-link but works
> with external serial devices, e.g. modems. I have yet to verify this
> statement myself.

Doesn't really make sense to me. RS232 is specified electrically, the
adapter doesn't know which kind of device it is talking to. I'm using
mine to connect to a TTL-RS232 adapter which sits on a DSL-router, so
it's like a "null-link".

> I tried to query the USB serial line's current parameters.
> Is there any other utilities that can do this for me?

Why do you need this, don't you know what you set it to? :)
There are ioctls for it and probably a terminal program will know how to
read and write it.

--
Servus,
Daniel

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