Define how long should the service centre try message delivery before giving up, failing delivery and deleting the message. A value of 0 means to use the service centre's default period.

The value specified is in seconds. Note that various protocols or implementations may round the value up (eg. to a minute or hour precision). The maximum validity period may vary depending on protocol or provider.

Connections with this interface SHOULD provide this property as a parameter for ConnectionManager.RequestConnection, with the DBus_Property flag.

For connections managed by the AccountManager, this property SHOULD be set via the Account Manager, by calling Account.UpdateParameters; the AccountManager provides change-notification, as long as all other clients cooperate by using it instead of setting this property directly.

Address for the messaging service centre. Typically (as is the case for GSM's SMSC), it's the ISDN / telephony address (ie. a phone number).

Connections with this interface SHOULD provide this property as a parameter for ConnectionManager.RequestConnection, with the DBus_Property flag.

For connections managed by the AccountManager, this property SHOULD be set via the Account Manager, by calling Account.UpdateParameters; the AccountManager provides change-notification, as long as all other clients cooperate by using it instead of setting this property directly.

The International Mobile Subscriber Identifier, if it exists. This would originate from a SIM card. If the IMSI is unknown, this will contain an empty string ("").

Determines whether SMSes containing characters that do not fit into a 7‐bit GSM character set should be sent as UCS‐2, or lossily recoded. If False (which SHOULD be the default), messages will be sent with no loss of fidelity (at the potential financial cost of using twice as many SMSes); if True, the message will be recoded in an implementation‐specific way to fit into a country‐specific GSM reduced character set.

Connections with this interface SHOULD provide this property as a parameter for ConnectionManager.RequestConnection, with the DBus_Property flag.

For connections managed by the AccountManager, this property SHOULD be set via the Account Manager, by calling Account.UpdateParameters; the AccountManager provides change‐notification, as long as all other clients cooperate by using it instead of setting this property directly.