Philips TEA1069N-C1, TEA1069H-C1, TEA1069AH-C1 Datasheet

INTEGRATED CIRCUITS

DATA SHEET

TEA1069; TEA1069A

Versatile speech/dialler/ringer with music-on-hold

Product specification

1998 Jan 08

Supersedes data of 1996 Dec 10

File under Integrated Circuits, IC03

Philips Semiconductors	Product specification

Versatile speech/dialler/ringer with

TEA1069; TEA1069A

music-on-hold

FEATURES

Speech part

∙Voltage regulator with adjustable static resistance

∙Low DC line voltage; operates down to 1.6 V (excluding polarity guard)

∙Supply for dialler part and peripherals (not stabilized)

∙Symmetrical high-impedance inputs (64 kΩ) for dynamic, magnetic, or piezoelectric microphones

∙Asymmetrical high-impedance input (32 kΩ) for electret microphones

∙Asymmetrical earpiece output for dynamic, magnetic, or piezoelectric earpieces

∙Internal mute to disable speech during dialling

∙Confidence tone during DTMF dialling

∙Line-loss compensation (line-current dependent) for microphone and earpiece amplifiers

∙Gain-control curve adaptable to the exchange supply.

Dialler part

∙Pulse/DTMF and mixed mode dialling

∙Last Number Redial (LNR), up to 32 digits

∙13 repertory numbers (3 direct and 10 indirect) or

10 repertory numbers (10 direct), up to 32 digits, with a maximum of 224 digits in total

∙Repertory and redial memory integrity check (memory contents check)

∙Notepad memory function

∙Flash and earth register recall

∙Dial mode output

∙Access pause generation and termination

∙Function keys for: store, memory recall, register recall, LNR, pause, hold, mute, hook

∙Keytone generation

∙Hands-free control

∙Volume control in hands-free mode (VOL+/VOL−)

∙Hold function

∙Mute function

∙Music-on-hold

∙Diode options:

–DTMF tone burst/pause time

–make/break ratio

–access pause time

–pulse or DTMF mode selection

–register recall (earth and flash times)

–keyboard layout selection

–selection for german requirements

–hold/mute mode selection.

Ringer part

∙Ringer input frequency discrimination

∙Ringer melody generation (3-tone)

∙Ringer melody selection/volume control via keyboard

∙Diode option: ringer frequency selection.

GENERAL DESCRIPTION

The TEA1069 and TEA1069A contain all the functions needed to build a highly featured, high-performance fully electronic telephone set.

The device incorporates a speech/transmission part, a dialler part and a ringer part. By offering a wide range of possible adaptations for each part, the TEA1069 and TEA1069A application can be easily adapted to meet different requirements.

The TEA1069A offers some different timings and diode options compared to the TEA1069.

Where pin numbers are mentioned in this data sheet we refer to the TEA1069N, unless otherwise indicated.

Speech part

The speech/transmission part performs all speech and line interface functions required in electronic sets. It operates at line voltages down to 1.6 V DC to facilitate the use of more telephones connected in parallel.

Dialler part

The dialler part offers a 32-digit Last Number Redial (LNR) and 13 memories. Hands-free control is included allowing the TEA1069 and TEA1069A to be used not only in basic telephones, but also in feature phones offering hands-free dialling via the TEA1083 call-progress monitor IC and/or full hands-free operation via the TEA1093 hands-free IC. The hold function allows the user to suspend the conversation and resume the call either on the same phone or on a parallel phone. Additionally through the music-on-hold function a melody is transmitted while the set is put on hold. The keytones provide in a buzzer an audible feedback of a valid key pressed.

1998 Jan 08

2

Philips Semiconductors	Product specification

Versatile speech/dialler/ringer with

TEA1069; TEA1069A

music-on-hold

Ringer part

The ringer part offers a discriminator input which enables the tone output as soon as a valid ring frequency is detected. It offers a melody based on 3 tones with programmable melody and volume via keyboard.

ORDERING INFORMATION

TYPE		PACKAGE
NUMBER	NAME	DESCRIPTION	VERSION
TEA1069N	SDIP42	plastic shrink dual in-line package; 42 leads (600 mil)	SOT270-1
TEA1069H	QFP44	plastic quad flat package; 44 leads (lead length 1.3 mm);	SOT307-2
		body 10 × 10 × 1.75 mm
TEA1069AH	QFP44	plastic quad flat package; 44 leads (lead length 1.3 mm);	SOT307-2
		body 10 × 10 × 1.75 mm

1998 Jan 08

3

08 Jan 1998

4

																																									VCC													LN					DIAGRAMBLOCK	speech/dialler/ringerVersatile hold-on-music
										KT/EARTH									DP/FL					MOH/DMO									MUTE												IR						AGC
												8									20						27										35					36					6				38			40
												(2)									(15)						(22)										(31)					(32)					(44)				(34)			(36)
						DIALLER
DIODE			34 (30)																																													SPEECH
			33 (29)											RECALL											PULSE																														(40) 2
ROW5																																																										GAR
			32 (28)
ROW4
			31 (27)
ROW3
ROW2			30 (26)																																													RECEIVE
																																																SECTION
			29 (25)
ROW1								KEYBOARD					KEY-												MUTE																														(39) 1
			14 (8)																																																							QR
COL6								DETECTOR					TONE
			15 (9)																																																									with
			17 (12)
COL5			16 (10)
COL4
COL3
			18 (13)											TONE										HOLD
COL2																																																TRANSMIT							(37) 41
			19 (14)										GENERATOR											LOGIC																																		GAS1
COL1			9 (3)																																													SECTION							(38) 42
CSI																			TEA1069																									dB														GAS2
			10 (4)																TEA1069A
XTAL1
			11 (5)					TIMING/
XTAL2
RESET			12 (6)					CONTROL										RINGER																												SUPPLY
			13 (7)
CE/FDI																	DETECTOR/
																GENERATOR																																												TEA1069;
VDD			25 (20)
																																											(11, 18
										(24)				(19)						(21)					(17)						(16)				(1)			(42)			(41)							(33)		(43)				(35)
																																											and 23)
										28				24						26					22						21				7			4			3		23					37		5				39
																															pagewidthfull																													TEA1069A
																																			MIC+							VEE					REG		STAB				SLPE
									HF				TONE					VOL1 VOL2											HOLD																											MBH195
																															handbook,	DTMF								MIC−
Pin numbers in parenthesis refer to the TEA1069H and TEA1069AH.
																						Fig.1					Block diagram.

Semiconductors Philips

specification Product

Philips Semiconductors	Product specification

Versatile speech/dialler/ringer with

TEA1069; TEA1069A

music-on-hold

PINNING

	SYMBOL			PIN		DESCRIPTION
			SOT270-1		SOT307-2
	QR		1		39	receiving amplifier output
	GAR		2		40	gain adjustment; receiving amplifier
	MIC−		3		41	inverting microphone input
	MIC+		4		42	non-inverting microphone input
	STAB		5		43	current stabilizer
	IR		6		44	receiving amplifier input
	DTMF		7		1	dual-tone multi-frequency input
	KT/EARTH		8		2	keytone/earth recall output
	CSI		9		3	cradle switch input
	XTAL1		10		4	oscillator input
	XTAL2		11		5	oscillator output
	RESET		12		6	reset input
	CE/FDI		13		7	chip enable/frequency discrimination input
	COL6		14		8	keyboard column input 6
	COL5		15		9	keyboard column input 5
	COL4		16		10	keyboard column input 4
	COL3		17		12	keyboard column input 3
	COL2		18		13	keyboard column input 2
	COL1		19		14	keyboard column input 1
	DP/FL		20		15	dial pulse/flash output
	HOLD		21		16	hold control input
	VOL2		22		17	volume 2 output
	VEE		23		11, 18, 23	negative line terminal
	TONE		24		19	tone generator output
	VDD		25		20	dialler/ringer part supply voltage
	VOL1		26		21	volume 1 output
	MOH/DMO		27		22	music on hold/dial mode output
	HF		28		24	hands-free control output
	ROW1		29		25	keyboard row input/output 1
	ROW2		30		26	keyboard row input/output 2
	ROW3		31		27	keyboard row input/output 3
	ROW4		32		28	keyboard row input/output 4
	ROW5		33		29	keyboard row input/output 5
	DIODE		34		30	diode option output
			35		31	mute output, active LOW
	MUTE
	VCC		36		32	speech part supply voltage
	REG		37		33	(DC) line voltage regulator decoupling
	AGC		38		34	automatic gain control input

1998 Jan 08

5

Philips Semiconductors	Product specification

Versatile speech/dialler/ringer with

TEA1069; TEA1069A

music-on-hold

SYMBOL		PIN		DESCRIPTION
	SOT270-1		SOT307-2
SLPE	39		35	slope (DC resistance) adjustment
LN	40		36	positive line terminal
GAS1	41		37	gain adjustment; transmitting amplifier
GAS2	42		38	gain adjustment; transmitting amplifier

handbook, halfpage
QR	1		42		GAS2
GAR	2		41		GAS1
MIC−
	3		40		LN
MIC+
	4		39		SLPE
STAB	5		38		AGC
IR	6		37		REG
					VCC
DTMF	7		36
KT/EARTH	8		35		MUTE
CSI					DIODE
	9		34
XTAL1	10		33		ROW5
XTAL2		TEA1069N			ROW4
	11		32
RESET	12		31		ROW3
CE/FDI					ROW2
	13		30
COL6	14		29		ROW1
COL5					HF
	15		28
COL4	16		27		MOH/DMO
COL3					VOL1
	17		26
					VDD
COL2	18		25
COL1					TONE
	19		24
					VEE
DP/FL	20		23
HOLD	21		22		VOL2
		MBH196

Fig.2 Pin configuration (SOT270-1).

1998 Jan 08

6

Philips Semiconductors	Product specification

Versatile speech/dialler/ringer with

TEA1069; TEA1069A

music-on-hold

			IR		STAB		MIC+		MIC−		GAR		QR		GAS2		GAS1		LN		SLPE		AGC
			44		43		42		41		40		39		38		37		36		35		34
DTMF	1
KT/EARTH
	2
CSI
	3
XTAL1	4
XTAL2	5
											TEA1069H
RESET	6
										TEA1069AH
CE/FDI
	7
COL6	8
COL5
	9
COL4
	10
VEE
	11
			12		13		14		15		16		17		18		19		20		21		22
			COL3		COL2		COL1		DP/FL		HOLD		VOL2		V		TONE		V		VOL1		MOH/DMO
															EE				DD

33 REG

32 VCC

31 MUTE

30 DIODE

29 ROW5

28 ROW4

27 ROW3

26 ROW2

25 ROW1

24 HF

23 VEE

MBH784

Fig.3 Pin configuration (SOT307-2).

FUNCTIONAL DESCRIPTION

Speech part

For numbering of components refer to Figs 28 and 29.

SUPPLIES VCC, LN, SLPE, REG AND STAB

Power for the IC and its peripheral circuits is usually obtained from the telephone line (see Fig.4).

The circuit creates a stabilized voltage (Vref = 3.7 V) between LN and SLPE. This reference voltage is temperature compensated and can be adjusted by means of an external resistor RVA. It can be increased by connecting an RVA resistor (R60) between REG and SLPE or decreased by connecting an RVA resistor (R61) between REG and LN. This internal voltage reference is decoupled by capacitor C3 between REG and VEE.

This decoupling capacitor realises the set impedance conversion from its DC value to its AC value in the audio frequency range.

The internal transmission part of the circuitry (including the earpiece amplifier) is supplied from VCC. This voltage supply is derived from the LN voltage via a dropping resistor (R1) and must be decoupled by a capacitor (C1) between VCC and VEE. This supply point may also be used to supply the dialler/ringer (VDD) part or external circuit e.g. electret microphone.

The DC current flowing into the set is determined by the exchange supply voltage Vexch, the feeding bridge

resistance Rexch and the DC resistance of the telephone line Rline. When the line current (Iline) is more than 0.5 mA greater than the sum of the IC supply current (ICC) and the

current drawn by the peripheral circuitry connected to VCC (Ip), the excess current is shunted to SLPE via LN.

1998 Jan 08

7

Philips Semiconductors	Product specification

Versatile speech/dialler/ringer with

TEA1069; TEA1069A

music-on-hold

Rline	Iline	R1
ISLPE + 0.5 mA			ICC
TEA1069		LN	VCC
TEA1069A				Ip
Rexch
DC			0.5 mA
AC			C1	peripheral
				circuits
Vexch
			VEE
REG	STAB	SLPE
	ISLPE
C3	R5	R9
				MBH197
Fig.4	Supply arrangement.

Thus, the regulated voltage on the line terminal (VLN) can be calculated as:

VLN = Vref + ISLPE ´ R9 , where

æ	+ Ip + 0.5 ´ 10	–3	ö
ISLPE = Iline –è ICC			Aø

Vref is the internally generated temperature compensated reference voltage of 3.7 V and R9 is an external resistor connected between SLPE and VEE.

The circuit has an internal current stabilizer operating at a level determined by resistor R5 connected between STAB and VEE.

In normal use the value of R5 would be 3.6 kW and the value of R9 would be 20 W.

Changing the value of R5 or R9 will affect microphone gain, DTMF gain, gain control characteristics, sidetone level, maximum output swing on LN and the DC characteristics (especially at low line current).

At line currents below 9 mA the internal reference voltage is automatically adjusted to a lower value (typically 1.6 V

at 1 mA). This means that more sets can be operated in parallel with DC line voltages (excluding the polarity guard) down to an absolute minimum voltage of 1.6 V. At line currents below 9 mA the circuit has limited sending and receiving levels.

Under normal conditions, when ISLPE >> ICC + 0.5 mA + Ip, the static behaviour of the circuit is that of a 3.7 V regulator

diode (Vref) with an internal resistance equal to that of R9. In the audio frequency range the dynamic impedance is largely determined by R1. Figure 5 shows the equivalent impedance of the circuit.

Current (Ip) available from VCC for the dialler part and peripheral circuits depends on the external components used. Figure 6 shows this current for VCC > 2.2 V. When

MUTE is HIGH i.e. when the receiving amplifier (supplied from VCC) is driven, the available current is further reduced. Current availability can be increased by connecting the supply IC TEA1081 in parallel with R1, or by increasing the DC line voltage by means of an external resistor (RVA = R60) connected between REG and SLPE.

1998 Jan 08

8

Philips Semiconductors	Product specification

Versatile speech/dialler/ringer with

TEA1069; TEA1069A

music-on-hold

LN
Leq	R p	R1
V ref	REG	VCC
SLPE
R9	C3	C1
20 Ω	4.7 μF	100 μF
VEE		MGD489

Leq = C3 × R9 × Rp.

Rp = 16.2 kΩ.

Fig.5 Equivalent impedance circuit.

2.4				MSA504
	(1)
I p
(mA)
	(2)
1.6
0.8
0
0	1	2	3	4

VCC (V)

VCC > 2.2 V; Iline = 15 mA at VLN = 4 V; R1 = 620 Ω; R9 = 20 Ω.

(1)Ip = 2.1 mA. The curve is valid when the receiving amplifier is not driven or when MUTE = LOW.

(2)Ip = 1.7 mA. The curve is valid when MUTE = HIGH and the receiving amplifier is driven; Vo(rms) = 150 mV, RL = 150 Ω.

Fig.6 Typical current IP available from VCC for peripheral circuitry.

1998 Jan 08

9

Philips Semiconductors	Product specification

Versatile speech/dialler/ringer with

TEA1069; TEA1069A

music-on-hold

MICROPHONE INPUTS MIC+ AND MIC− AND GAIN PINS GAS1 AND GAS2

The circuit has symmetrical microphone inputs. Its input impedance is 64 kΩ (2 × 32 kΩ) and its voltage gain is typically 52 dB (when R7 = 68 kΩ). Dynamic, magnetic, piezoelectric or electret (with built-in FET source followers) microphones can be used. Microphone arrangements are illustrated in Fig.7.

handbook, full pagewidth

															36 (32)
4 (42)																			3 (41)	VCC								4 (42)				MIC+
					MIC+															MIC−
				(1)
				3 (41)												4 (42)														3 (41)		MIC−
					MIC−															MIC+
																				VEE												MBH198
																					23 (18)
a. Magnetic or dynamic											b. Electret microphone.												c. Piezoelectric microphone.
	microphone.

Pin numbers in parenthesis refer to the TEA1069H and TEA1069AH.

(1) Resistor may be connected to reduce the terminating impedance.

Fig.7 Alternative microphone arrangements.

The gain of the microphone amplifier can be adjusted between 44 dB and 52 dB to suit the sensitivity of the transducer in use. The gain is proportional to the value of R7 which is connected between GAS1 and GAS2. Stability is ensured by two external capacitors, C6 connected between GAS1 and SLPE and C17 connected between GAS1 and VEE. The value of C6 is 100 pF but this may be increased to obtain a first-order low-pass filter. The value of C17 is 10 times the value of C6. The cut-off frequency corresponds to the time constant R7 × C6.

RECEIVING AMPLIFIER IR, QR AND GAR

The receiving amplifier has one input (IR) and one output (QR). Earpiece arrangements are illustrated in Fig.8. The IR to QR gain is typically 31 dB (when R4 = 100 kΩ).

It can be adjusted between 20 and 31 dB to match the sensitivity of the transducer in use.

The gain is set with the value of R4 which is connected between GAR and QR. The overall receive gain, between LN and QR, is calculated by subtracting the anti-sidetone network attenuation (32 dB) from the amplifier gain.

Two external capacitors, C4 and C7, ensure stability. C4 is normally 100 pF and C7 is 10 times the value of C4.

The value of C4 may be increased to obtain a first-order low-pass filter. The cut-off frequency will depend on the time constant R4 × C4.

The output voltage of the receiving amplifier is specified for continuous-wave drive. The maximum output voltage will be higher under speech conditions where the peak to RMS ratio is higher.

1998 Jan 08

10

Philips Semiconductors	Product specification

Versatile speech/dialler/ringer with

TEA1069; TEA1069A

music-on-hold

k, full pagewidth

1 (39)								1 (39)			(1)			1 (39)			(2)
	QR								QR						QR
23 (18)								23 (18)						23 (18)
	VEE								VEE						VEE		MBH199
a. Dynamic earpiece.								b. Magnetic earpiece.						c. Piezoelectric earpiece.

Pin numbers in parenthesis refer to the TEA1069H and TEA1069AH.

(1)Resistor may be connected to prevent distortion (inductive load).

(2)Resistor is required to increase the phase margin (capacitive load).

Fig.8 Alternative receiver arrangements.

DUAL TONE MULTI-FREQUENCY INPUT DTMF

When the DTMF input is enabled (MUTE is LOW) dialling tones may be sent on to the line. The voltage gain from DTMF to LN is typically 25.5 dB (when R7 = 68 kΩ) and varies with R7 in the same way as the microphone gain. The tones can be heard in the earpiece at a low level (confidence tone).

AUTOMATIC GAIN CONTROL INPUT AGC

Automatic line loss compensation is achieved by connecting a resistor (R6) between AGC and VEE. The automatic gain control varies the gain of the

microphone amplifier and the receiving amplifier in accordance with the DC line current.

The control range is 5.8 dB which corresponds to a line length of 5 km for a 0.5 mm diameter twisted-pair copper cable with a DC resistance of 176 Ω/km and average attenuation of 1.2 dB/km. Resistor R6 should be chosen in accordance with the exchange supply voltage and its feeding bridge resistance (see Fig.9 and Table 1).

The ratio of start and stop currents of the AGC curve is independent of the value of R6. If no automatic line-loss compensation is required the AGC pin may be left open-circuit. The amplifiers, in this condition, will give their maximum specified gain.

1998 Jan 08

11

Philips Semiconductors	Product specification

Versatile speech/dialler/ringer with

TEA1069; TEA1069A

music-on-hold

R6 = ∞

MGD490

0

G v (dB)

2

4

78.7 kΩ 110 kΩ 140 kΩ

5.8

6

0

20

40

60

80

100

120

140

I line (mA)

Fig.9 Variation of gain as function of line current with R6 as parameter.

Table 1 Values of resistor R6 for optimum line-loss compensation at various values of exchange supply voltage (Vexch) and exchange feeding bridge resistance (Rexch); R9 = 20 Ω

Vexch (V)			R6 (kΩ)
	Rexch = 400 Ω	Rexch = 600 Ω		Rexch = 800 Ω	Rexch = 1000 Ω
36	100	78.7		−	−
48	140	110		93.1	82
60	−	−		120	102

1998 Jan 08

12

Philips Semiconductors	Product specification

Versatile speech/dialler/ringer with

TEA1069; TEA1069A

music-on-hold

SIDETONE SUPPRESSION

Suppression of the transmitted signal in the earpiece is obtained by the anti-sidetone network comprising R1//Zline,

R2, R3, R8, R9 and Zbal (see Fig.10). The maximum compensation is obtained when the following conditions

are fulfilled:

R9 × R2 = R1 × ( R3 + R8)	(1)
( R8 + R9)	(2)
k = R3 × ----------------------------
( R2 × R9)
Zbal = k × Zline	(3)

The scale factor k is chosen to meet the compatibility with

a standard capacitor from the E6 or E12 series for Zline. In practice, Zline varies considerably with the line type and length. Therefore, the value chosen for Zbal should be for

an average line length thus giving optimum setting for short or long lines.

Example: the balance impedance Zbal at which the optimum suppression is present can be calculated as

follows:

suppose Zline = 210 Ω + (1265 Ω//140 nF) representing a 5 km line of 0.5 mm diameter, copper, twisted-pair cable matched to 600 Ω (176 Ω/km; 38 nF/km).

When k = 0.64 then R8 = 390 Ω; Zbal = 130 Ω + (820 Ω//220 nF).

The anti-sidetone network for the TEA1069 and TEA1069A shown in Fig.10 attenuates the signal received from the line by 32 dB before it enters the receiving amplifier.

The attenuation is almost constant over the whole audio-frequency range. Figure 11 shows a conventional Wheatstone bridge anti-sidetone circuit that can be used as an alternative. Both bridge types can be used with either resistive or complex set impedances. More information on the balancing of anti-sidetone bridges can be found in our publication “Applications Handbook for Wired telecom systems, IC03b”, order number

9397 750 00811.

	LN
R1	R2
Zline
	IR
VEE	im
	Rt

R3

R9

R8

Zbal

SLPE

MSA500 - 1

Fig.10 Equivalent circuit of TEA1069 and TEA1069A anti-sidetone bridge.

1998 Jan 08

13

Philips Semiconductors	Product specification

Versatile speech/dialler/ringer with

TEA1069; TEA1069A

music-on-hold

		LN
	R1	Zbal
	Zline
		im	IR
	VEE		Rt
	R9	R8	RA
		SLPE
			MSA501 - 1

Fig.11 Equivalent circuit of an anti-sidetone network in a Wheatstone bridge configuration.

Dialler and ringer part

SUPPLY VOLTAGE: PINS VDD AND VEE

The power supply must be maintained for data storage. The RAM retention voltage (standby supply voltage) may drop down to 1.0 V. Applying a large capacitor across the supply terminals can retain the memory if power connections are broken. The minimum operation voltage is 2.5 V. The internal power-on reset is enabled for a voltage below this minimum operation voltage.

OSCILLATOR INPUT/OUTPUT: PINS XTAL1 AND XTAL2

Time base for the TEA1069 and TEA1069A is a crystal-controlled on-chip oscillator which is completed by connecting a 3.579545 MHz crystal or ceramic resonator between XTAL1 and XTAL2. The oscillator starts when VDD reaches the operation voltage level and

CE/FDI = HIGH. The following types of ceramic resonators are recommended:

∙Kyocera PBRC3.58ARPC10 (wired)

∙Kyocera KBR3.58MSATRPC10 (SMD)

∙Murata CSA3.58MG310VA (wired).

RESET INPUT: PIN RESET

Pin RESET is an input to the internal reset circuit. When RESET = HIGH, it can be used to initialize the TEA1069 and TEA1069A which is normally done by the CE/FDI input. The on-chip power-on reset generates a reset pulse if VDD drops below 2.5 V. In this event a proper start-up

occurs after the supply voltage rises above the minimum operation voltage level again.

During and directly after reset pins 14 to 19, 21, 29 to 32, 34 and 35 are set HIGH; pins 8, 20, 22, 26 to 28 and 33 are set to LOW.

The RESET pin can be connected to VEE, preferably via a resistor of 100 kΩ to 1 MΩ, which will save leakage current. A capacitor connected to VDD can be used to extend the reset time, in case a longer reset is desirable.

To prevent the dialler from reacting on voltage disturbances on the telephone line a time-out is active. The dialler returns to standby state if the voltage on the line has disappeared for more than this reset-delay time (trd).

CHIP ENABLE/FREQUENCY DISCRIMINATOR INPUT:

PIN CE/FDI

This active HIGH input is used to initialize part of the system, to select the on-line, standby, or ringer mode and to detect line power breaks. To keep the TEA1069 and TEA1069A in the on-line mode, CE/FDI has to be HIGH.

In the exchange, several AC signals can be superimposed on the DC signal, e.g. dialling tone, busy tone, disturbances (like line power breaks), and the ringer signal. The ringer signal is evaluated, and checked if its frequency is within the limits of the frequency interval as set by the diode option RFS. It is assumed that the ringer frequency at pin CE/FDI is the double of the frequency present on the telephone line.

1998 Jan 08

14