Symbian OS maintains a database of communications-related configuration settings. This database is called the Comms database, and is always available on any Symbian platform. The Comms database is accessed and manipulated by various tools and applications that need to manage voice or data transmissions using any kind of network technology. The Comms database contains the necessary configuration data for managing any kind of data connection on any kind of network.
For example, to configure a modem, you need to set fields such as:
Name=Default Modem
PortName=COMM::0
DataBits=8
StopBits=1
Parity=NONE
Rate=115200
You can manage the database statically using the command-line tools CED and CEDDUMP, or dynamically using the COMMSDAT API.
For information about the mechanics of configuring the Comms database using the CED and CEDDUMP tools, see Configuring Comms database using CED and CEDDUMP
For information on the file formats supported by CED and CEDDUMP, see Comms database configuration file format
For reference documentation on all the fields of all the public tables in the Comms database, see Comms Database Reference in the CommsDat engineering documentation.
For reference documentation about the APIs that manage the Comms database, see Comms infras COMMSDAT
This diagram shows the relationship between a Client process and CommDb
There are two potential client stakeholders:
Clients that are setting and displaying configuration data
These are typically clients in other parts of the OS.
Device Provisioning and SyncML set and read the data
Messaging APIs read the data
Watchers gather information about the Comm Server
Some utilities use Comm Db to read Signal Strength.
Clients obeying and using the configuration data.
This includes ESock, Telephony and Serial Server C32.
DHCP and DNS are client utilities which run alongside a Comms Process.
There are two separate aspects to configuring CommDb
Configuring Comms Framework stack (IAP preferences, Network Service tables).
Configuring CommDb to manage the behaviour of Comms Components
There are five key use cases:
CSD Connection(Circuit switched phone call). For information on this use case see How to configure a CSD Connection (Circuit switched call)in the CommsDat Engineering documentation.
PSD Connection(GPRS). For information on this use case see How to configure a PSD Connection in the CommsDat Engineering documentation.
VPN Connection(Virtual Network)
Ethernet
3G
WIFI, DHCP and PPP are other potential use-cases. Some components may also rely on an ini file as well as being configured by the database e.g PPP.