Huawei modem problem E3531

After plugging in a Huawei USB HSPA Modem and doing lsusb I get:

Bus 001 Device 006: ID 12d1:1f01 Huawei Technologies Co., Ltd. E353/E3131 (Mass storage mode)

Tried the usb_modeswitch command as per the tutorial, but it didn’t do anything. Searched around and found this example for the RaspberryPi and the E3531

sudo usb_modeswitch -v 0x12d1 -p 0x1f01 -V 0x12d1 -P 0x1001 -M “55534243123456780000000000000011062000000100000000000000000000”

Another lsusb and I get:

Bus 001 Device 005: ID 12d1:1001 Huawei Technologies Co., Ltd. E169/E620/E800 HSDPA Modem

First doubt is the E169/E620/E800 HSDPA Modem tacked on the end, however performing the next step I got:

dave@dave-AOD255E:~$ sudo pon e303
/usr/sbin/pppd: In file /etc/ppp/peers/e303: unrecognized option ‘dev/ttyUSB0’

Many hours searching and the only useful suggestion was to ensure the /dev entry was rw, which it is

dave@dave-AOD255E:/dev$ ls -la ttyUSB*
crw-rw---- 1 root dialout 188, 0 Sep 8 23:23 ttyUSB0
crw-rw---- 1 root dialout 188, 1 Sep 8 23:21 ttyUSB1
crw-rw---- 1 root dialout 188, 2 Sep 8 23:22 ttyUSB2

I feel this must be a common problem so was hoping someone with experience would point me in the right direction.

Thank you,

The script is correct, the forward slash must have gotten deleted at my end