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Caller ID

Analog caller ID is a local-access feature delivered to the customer-premises equipment by the local exchange carrier (LEC). It provides the called terminal equipment (TE) with the directory number and, optionally, the directory name of the calling party, along with the date and time. The data are delivered via a 1200-bps data modem or DTMF during the silent interval of the first ringing cycle for on-hook transmission or anytime for off-hook transmission.

The 60085 CID Transmitter allows the developer of analog access equipment to offer caller ID compatible with PTT specifications in much of the world. In some situations, the message delivery sequence must be coordinated with events outside the scope of the transmitter, such as loop reversals or ringing. The task that controls the CID Transmitter is aware of the timing of these events and provides a signal to the CID Transmitter to indicate when transmission must begin and end. For the off-hook transmission, the TAS (TE Alerting Signal) tone generation and timing are implemented by the CID transmitter. When needed, the Channel Seizure Signal (CSS) and Mark Signal will be generated by the CID transmitter.

The formatting of the data as well as checksum generation are handled by the controlling application and are outside of the scope of this document. Data input/output are via 16-bit linear PCM buffers.

The 60085 CID Transmitter allows the OEM to meet the requirements of the following standards:

  1. GR-30-CORE, LSSGR: Voiceband Data Transmission Interface Section 6.6, Telcordia Technologies, December 1998.
  2. ETS 300 659-1, Public Switched Telephone Network (PSTN); Subscriber line protocol over the local loop for display (and related) services; Part 1 Onhook data transmission, ETSI, February 1997.
  3. ETS 300 659-2, Public Switched Telephone Network (PSTN); Subscriber line protocol over the local loop for display (and related) services; Part 2: Off-hook data transmission, ETSI, September 1997

The Caller ID Transmitter provides the ability to transmit caller identification data, in both the on-hook and off-hook states. For the on-hook state, the algorithm implementation will be limited to that of data transmission during the first long silent period between two ring cycles. The implementation is compliant with both Telcordia and ETSI specifications. The following are the major differences between the two standards:

Differences Between Telcordia and ETSI Caller ID
Function Telcordia specifications ETSI specifications
FSK Modem frequencies Mark = 1200 +/- 12 Hz
Space = 2200 +/- 12 Hz
V.23 Mode 2 [Error! Reference source not found.]
Mark = 1300 +/- 10 Hz
Space = 2100 +/- 10 Hz
DT-AS Tone duration 80 – 85 ms 100 ms +/- 10 ms

The CID transmitter's external interface is defined by a simple four-function API as shown in the figure below. CIDDbInit initializes the CID transmitter database whereas CIDGlobalInit does the initialization of the global parameters. Commands and data are supplied to the CID transmitter by the CIDMsg function, which calls cid_processControlEvent. The output PCM data are generated by the CID function, which calls cid_processMedia.

Figure 1. External Interface

Features

  • Compliance: GR-30-CORE, LSSGR: Voiceband Data Transmission Interface, ETS 300-659-1, ETS 300-659-2
  • Generates FSK ID data, TAS, CSS, and Mark Signal
  • Easy-to-use interface
  • TI 'C5000 and 'C6000 supported

Ordering Information

PN 60085     C-Reference Source Code
PN 60085-1  C-Reference plus TI TMS320C5400
PN 60085-2  C-Reference plus TI TMS320C6000
PN 60085     C-Reference plus ARC Cores ARCTangent

Commetrex, Open Telecommunications Framework, PowerFax, PowerRelay, OpenMedia, Media Stream Gateway, OTF Kernel, MSP-320, MSP-H8, PortableT30, and TerminatingT38 are trademarks of Commetrex. All other trademarks are the property of their respective holders. Specifications subject to change without notice.