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3.5.2
Phase 2 or Location Determination
The CM52 can support location determination, primarily to satisfy an FCC requirement for E911 phase 2
support. The CM52 is not a GPSOne solution, but rather provides the network the GPS data from a
standalone GPS receiver (note the GPS receiver has to provide pseudorange data). The GPS receiver can be
external to the CM52 or the CM52 can be ordered with a Sony 2951 GPS receiver on board.
If the GPS receiver is external, the application is responsible for providing the GPS pseudorange data via the
AT*EPDPR command. The module will request the application for the data by an unsolicited message
(*EPDPR). The CM52 is responsible for acquiring any CDMA related information, most notably the CDMA
pilot phase measurement data to support AFLT and hybrid measurements.
If the GPS receiver is embedded in the CM52, location determination will be completely handled by the CM52.
There are no software requirements placed upon the customer application.
Because the current focus is on data only solutions, the location determination technique has not been
certified by any carrier at this time.
3.6
Short Message Service
The module provides the functional capability to create and send text messages (MO), as well as receive text
messages (MT) across the air interface. The data format can be either string data represented as printable IRA
characters, or binary data represented as hex-coded octets.
The maximum length of data sent in an SMS transmission is 255 bytes, though typically the carrier further
reduces the allowable size to something less. The actual user data is directly dependent on how much
message overhead is present. Therefore, a significant number of optional SMS header data fields could
substantially reduce the user data space.
According to IS2000, SMS messages can be sent either on the access channel or on a traffic channel; SMS
messages can be received either on the paging channel or on a traffic channel. The carrier/network controls
the medium used for SMS traffic. If sending an SMS message on the access channel fails, the module will
always try to send the message on a traffic channel. As a best practice, enable the SMS MO status
unsolicited message. The unsolicited messages indicate the status of the outgoing message.
SMS messages can be sent and received while a traffic channel is present for other uses besides SMS. For
example; if a voice call is active, SMS messages can be handled simultaneously.
An outgoing SMS message can be sent before the module has registered with the network. An outgoing SMS
message is considered an implicit registration: the network has been made aware of the module through the
SMS request.
The following services are provided by the module for short message control:
•
Message formatting
The module formats short messages for transmission over the air interface.
•
Message reference assignment
The module assigns message reference numbers to new short messages that are transmitted over the
air interface.
•
Privacy Management
The module supports privacy criteria.
•
Message reporting
The module reports incoming messages that are received over the air interface.
The CM52 is not designed to store SMS messages. Message storage is a requirement that is handled by the
application. Therefore, the CM52 will not store outgoing messages at all. Because the module does not store
messages, it does not provide a retry mechanism. Instead, the module indicates to the application that the
Confidential
USERS MANUAL
Document number
1/198 17-4/FCP 101 3045 Uen
21(158)
Revision
D
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