QMI

The Qualcomm MSM Interface is a binary protocol that seeks to replace the Hayes AT command set for modems. It defines a set of services:

• CTL -- control
• DMS -- device management
• NAS -- network access
• WDS -- wireless data
• WDA -- wireless data administration
• WMS -- wireless messaging
• PDS -- position determination
• PBM -- phonebook management
• UIM -- user identification module
• OMA -- open management alliance

On Linux, QMI is primarily driven through the qmi-glib library and the qmicli tool, using the cdc-wdm and qmi_wwan drivers. A client context must be acquired from the CTL service to use most other services. Services implement "Requests" and "Indications": indications are sent to subscribed clients, while requests are bound to a client context, pipelined, and can be answered out of order. Input and output arguments are defined as TLVs (Type-Length Values).