Receiving FSK

Overview

The Receiving FSK feature uses the Resource Connect (0x0127) and Resource Information Notify (0x0141) messages that allow the host to receive FSK data from an off-hook channel. Refer to the call flow below.

Currently, the CSP supports sending Frequency Shift Keying (FSK) data containing On-hook Caller ID in the Outseize Control (0x002C) message and Off-hook Caller ID in the Resource Connect (0x0127) message. It also supports sending and receiving FSK data containing SMS DLL messages that comply with ETSI and CTSI (China Telecom) call flows.

The following API messages and TLVs have been modified. Refer to the detailed information in the API Reference for the modified APIs and TLVs.

Modified APIs

• The Resource Connect (0x0127) message supports the new resource type Receive FSK (0x010D) under the Mandatory TLV Resource Type (0x0602).

• The Resource Information Notify (0x0141) message supports the new resource type Receive FSK (0x010D) under the Mandatory TLV Resource Type (0x0602).

• The Call Processing Event (0x002E) message, field 0x50 DSP Series 2 FSK Events, supports new event types: FSK Receive Failed (0x0007) and FSK Receive Complete (0x0008).

Modified TLVs

• A new resource type Receive FSK (0x010D) has been added to the Resource Type (0x0602) TLV.

• A new data type Raw Data (0x0002) has been added to the FSK Data (0x0690) TLV. This TLV is used to send FSK data received from the DSP chip, without any modifications or formatting, to the host.