What does 装卸 mean here? My sentence is:

未来商店的购物车把手上装有购物助手----一个可随意装卸的无线电脑工具。

装卸的意思是: load-unload, transfer, assemble-disassemble

Maybe here '装卸‘ just means the 购物助手 'can be mounted on the shopping trolley if you wish'.

Or does 随意装卸的无线电脑‘ mean here 'the wireless computer can be freely programmed'? 

In that case 装卸 means 'program, upload any data, transfer data to'?
购物助手(shopping helper) is the topic
一个可随意装卸的无线电脑工具。'a wireless computer tool (device) that can be mounted and dismounted at will.'  is the comment on the topic. It explains what 购物助手 is.


Since 购物助手 is a device, 装卸(mount/dismount) here refers to the mounting and dismounting of the unit itself--  nothing to do with data upload and download.

By the way: 


'Data upload and download' in Chinese would be '数据(data)上传(up load)和下载(down load)'.  
Not '数据(data)装上(load up)和卸下(unload)'