USB modem shows up several times when listing

[sts-ryan-holton]

Hi, I've installed this library onto my Raspberry Pi 4, which has four USB ports, there's nothing plugged in to any of them. When I plug my HUAWEI USB modem into one of the ports and then run:

serialportgsm.list((err, result) => {
    console.log(result)
})

The modem shows up three times, with a different path on each. Here's the output:

[
  {
    path: '/dev/ttyUSB0',
    manufacturer: 'HUAWEI',
    serialNumber: undefined,
    pnpId: 'usb-HUAWEI_HUAWEI_Mobile-if00-port0',
    locationId: undefined,
    vendorId: '12d1',
    productId: '1c05'
  },
  {
    path: '/dev/ttyUSB1',
    manufacturer: 'HUAWEI',
    serialNumber: undefined,
    pnpId: 'usb-HUAWEI_HUAWEI_Mobile-if01-port0',
    locationId: undefined,
    vendorId: '12d1',
    productId: '1c05'
  },
  {
    path: '/dev/ttyUSB2',
    manufacturer: 'HUAWEI',
    serialNumber: undefined,
    pnpId: 'usb-HUAWEI_HUAWEI_Mobile-if02-port0',
    locationId: undefined,
    vendorId: '12d1',
    productId: '1c05'
  },
  {
    path: '/dev/ttyAMA0',
    manufacturer: undefined,
    serialNumber: undefined,
    pnpId: undefined,
    locationId: undefined,
    vendorId: undefined,
    productId: undefined
  }
]

How would I know which one to connect to from here?

[Apollon77]

In fact by default such devices expose several ports with special meanings. I needed to use USB2 with my stick (PCUI port) ... in fact you can try the lib with each port and you will see where it connects.

In the end sending

"^GETPORTMODE" shjould let you see which port is which

[Apollon77]

(sometimes also USB0 works directly)