MT88E46 Datasheet, PDF(21/23 Page) Zarlink Semiconductor Inc – Bellcore Compliant Calling Number Identification Circuit

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MT88E46 Datasheet, PDF (21/23 Pages) Zarlink Semiconductor Inc – Bellcore Compliant Calling Number Identification Circuit

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Advance Information MT88E46

CPE goes off-hook

CPE mutes handset, disables keypad

and performs MEI check (See TIA/EIA-777)

TIP/RING

PWDN

(Note 6)

Note 1

Off Hook CASen

(Note 6)

CAS

25ms

CPE sends

ACK

Note 5

30-40ms

Mark

Data

FSKen

(Note 6)

OSC2

DET

(Note 7)

Note 2

tPU

tDET2

tDW

Note 3

tCP

(Note 7)

DCLK

DATA

Data

CPE unmutes handset

and enables keypad

Speech

Note 4

tCA

A = 75-85ms

B = 0-100ms

C = 55-65ms

D = 0-500ms

E = 58-75ms

F = feature specific

G â¤ 50ms

Figure 17 - Application Timing: Bellcore Off-Hook Data Transmission, e.g. CIDCW

Notes:

1)In a CPE where AC power is not available, the designer may choose to switch over to line power when the CPE goes off-hook and

use battery power while on-hook. The CPE must also be CID (on-hook) capable because a CIDCW CPE includes CID functionality.

2)Non-FSK signals such as CAS, speech and DTMF tones are in the same frequency band as FSK. They will be demodulated and give

false data. Therefore the MT88E46 should be taken out of FSK mode when FSK is not expected.

3)If the CPE is the ACK-Sender, the MT88E46 may be put into FSK mode right after ACK has been sent. If the CPE is not the ACK-

Sender, the MT88E46 should be put into FSK mode at 30ms (min ACK delay) + 55ms (min ACK duration) = 85ms after the line

HIGH transition. In that case the FSK carrier detector may be activated by the ACK if both the ACK delay and the ACK duration are

at maximum. TR-NWT-000575 speciï¬es that ACK = DTMF âDâ for non-ADSI CPE, âAâ for ADSI CPE.

4)The MT88E46 should be taken out of FSK mode when CD has become inactive, or when more than 5 framing errors have been

detected in the message, or when more than 150ms of continuous Mark or Space has been detected.

5)In an unsuccessful attempt where the central ofï¬ce does not send the FSK signal, the CPE should unmute the handset and enable

the keypad after interval D has expired.

6)PWDN, Off Hook CASen and FSKen are internal signals decoded from CB0/1/2.

7)The DR/DET output pin is the DET signal when CAS detection is selected, the DR signal when FSK is selected.

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