The setting

I need to write program that to be able to use several types of barcode scanners, connected on USB port.

All these scanners have mode of type "serial port emulation" where (on my understanding) they should behave like simple byte stream device.

But one of the scanners behaves differently. It sends only fixed length (64 bytes) blocks, where the first byte is the length of the data, then the data bytes and padded with zeros up to the end of the block.

Every block can be read only in single read operation on the device. Even one read byte, causes the whole block to disappear from the IO stream.

The scanner is detected (using lsusb) as a HMI device:

Bus 001 Device 002: ID 05e0:0600 Symbol Technologies
Device Descriptor:
 bLength 18
 bDescriptorType 1
 bcdUSB 2.00
 bDeviceClass 0
 bDeviceSubClass 0
 bDeviceProtocol 0
 bMaxPacketSize0 64
 idVendor 0x05e0 Symbol Technologies
 idProduct 0x0600
 bcdDevice 0.01
 iManufacturer 1 Symbol Technologies, Inc, 2008
 iProduct 2 Symbol Bar Code Scanner
 iSerial 3 S/N:44F1BF6A7CCE45DEB787C6D4A63A1B62 Rev:PAACLS00-001-R015
 bNumConfigurations 1
 Configuration Descriptor:
 bLength 9
 bDescriptorType 2
 wTotalLength 34
 bNumInterfaces 1
 bConfigurationValue 1
 iConfiguration 8 Bus Powered
 bmAttributes 0xa0
 (Bus Powered)
 Remote Wakeup
 MaxPower 500mA
 Interface Descriptor:
 bLength 9
 bDescriptorType 4
 bInterfaceNumber 0
 bAlternateSetting 0
 bNumEndpoints 1
 bInterfaceClass 3 Human Interface Device
 bInterfaceSubClass 0
 bInterfaceProtocol 0
 iInterface 0
 HID Device Descriptor:
 bLength 9
 bDescriptorType 33
 bcdHID 1.10
 bCountryCode 0 Not supported
 bNumDescriptors 1
 bDescriptorType 34 Report
 wDescriptorLength 40
 Report Descriptors:
 ** UNAVAILABLE **
 Endpoint Descriptor:
 bLength 7
 bDescriptorType 5
 bEndpointAddress 0x81 EP 1 IN
 bmAttributes 3
 Transfer Type Interrupt
 Synch Type None
 Usage Type Data
 wMaxPacketSize 0x0040 1x 64 bytes
 bInterval 3
can't get device qualifier: Resource temporarily unavailable
can't get debug descriptor: Resource temporarily unavailable
Device Status: 0x0002
 (Bus Powered)
 Remote Wakeup Enabled

For comparison, here is the lsusb output about another scanner, that behaves as a normal byte stream device:

Bus 001 Device 003: ID 067e:0803 Intermec Technologies Corp. VCP, Barcode scanner
Device Descriptor:
 bLength 18
 bDescriptorType 1
 bcdUSB 1.10
 bDeviceClass 2 Communications
 bDeviceSubClass 2 Abstract (modem)
 bDeviceProtocol 0
 bMaxPacketSize0 64
 idVendor 0x067e Intermec Technologies Corp.
 idProduct 0x0803 VCP, Barcode scanner
 bcdDevice 2.58
 iManufacturer 1 Intermec
 iProduct 2 SR31T
 iSerial 0
 bNumConfigurations 1
 Configuration Descriptor:
 bLength 9
 bDescriptorType 2
 wTotalLength 67
 bNumInterfaces 2
 bConfigurationValue 1
 iConfiguration 0
 bmAttributes 0xa0
 (Bus Powered)
 Remote Wakeup
 MaxPower 500mA
 Interface Descriptor:
 bLength 9
 bDescriptorType 4
 bInterfaceNumber 0
 bAlternateSetting 0
 bNumEndpoints 1
 bInterfaceClass 2 Communications
 bInterfaceSubClass 2 Abstract (modem)
 bInterfaceProtocol 0
 iInterface 0
 CDC Header:
 bcdCDC 1.10
 CDC ACM:
 bmCapabilities 0x00
 CDC Union:
 bMasterInterface 0
 bSlaveInterface 1
 CDC Call Management:
 bmCapabilities 0x00
 bDataInterface 1
 Endpoint Descriptor:
 bLength 7
 bDescriptorType 5
 bEndpointAddress 0x81 EP 1 IN
 bmAttributes 3
 Transfer Type Interrupt
 Synch Type None
 Usage Type Data
 wMaxPacketSize 0x0008 1x 8 bytes
 bInterval 255
 Interface Descriptor:
 bLength 9
 bDescriptorType 4
 bInterfaceNumber 1
 bAlternateSetting 0
 bNumEndpoints 2
 bInterfaceClass 10 CDC Data
 bInterfaceSubClass 0
 bInterfaceProtocol 0
 iInterface 0
 Endpoint Descriptor:
 bLength 7
 bDescriptorType 5
 bEndpointAddress 0x82 EP 2 IN
 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 0x02 EP 2 OUT
 bmAttributes 2
 Transfer Type Bulk
 Synch Type None
 Usage Type Data
 wMaxPacketSize 0x0040 1x 64 bytes
 bInterval 0

The dmesg output on plugging in barcode scanner:

[19415.108131] usb 1-1: new full-speed USB device number 4 using xhci_hcd
[19415.252278] usb 1-1: New USB device found, idVendor=05e0, idProduct=0600
[19415.252295] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[19415.252305] usb 1-1: Product: Symbol Bar Code Scanner
[19415.252313] usb 1-1: Manufacturer: Symbol Technologies, Inc, 2008
[19415.252321] usb 1-1: SerialNumber: S/N:44F1BF6A7CCE45DEB787C6D4A63A1B62 Rev:PAACLS00-001-R015
[19415.273661] hid-generic 0003:05E0:0600.0008: hiddev0,hidraw6: USB HID v1.10 Device [Symbol Technologies, Inc, 2008 Symbol Bar Code Scanner] on usb-0000:00:10.0-1/input0

The question:

How to configure Linux to handle this scanner as a byte stream device?

Partial answer: If you do have the "special com port driver" for this scanner, and you do have a Windows computer, you can snoop the USB traffic under Windows in the initialization phase of the driver and find out how it switches to the serial configuration. That traffic can then be replayed in Linux using libusb etc.

USB snooping tools for Windows are e.g. usbsnoop or usbcap, google for more.

Looking at the HID descriptor may offer a simpler alternative, though.