austriamicrosystems Handsfree Line Interface Demoboard AN523/24 Key Features - Complete handsfree telephone with AS2523/24 Line Interface Jumper selectable AC impedance Easily configurable passive sidetone network on 8-pin socket PRELIMINARY APPLICATION NOTE Applications - Feature handsfree telephones AS2524 for handsfree telephones connected to a standard dialer AS2523 for handsfree telephones controlled via serial interface. General description PTT spec conformity This application note describes operation and features of the AS2523 and AS2524 Handsfree Line Interface IC including all external components necessary for the DB523 Demoboard, which is a handsfree telephone with a standard dialer interface on AS2524 and a serial interface on AS2523. The application notes hereafter should be understood as guidelines for other designs based on the AS252x circuit. No guarantee can be given for completeness or full conformity to PTT specification requirements. As requirements differ from country to country, each required parameter must be individually tested and adjusted, if necessary. Further guidelines for adjustment is given in the documents, listed in other applicable documents and papers. Revision 1.01, Preliminary Page 1 of 16 Application Note AN523/24 austriamicrosystems Table of Contents OTHER APPLICABLE DOCUMENTS AND PAPERS 3 Further Applications 3 REVISION STATUS 3 Revision history 3 Demo kit contents 3 GENERAL DESCRIPTION 3 Getting started 3 CONNECTOR AND JUMPER LOCATIONS 4 APPLICATION SCHEMATIC, ANALOG PART 5 DB523/24 DEMOBOARD: LAYOUT (TOP VIEW) 6 DB523/24 DEMOBOARD: COMPONENT PRINT 6 EXTERNAL COMPONENT SELECTION 7 Passive components 7 Transistors 7 COUNTRY SPECIFIC SETTINGS 7 Hardware and software settings AC impedance Sidetone cancellation Sending and receiving frequency response 7 7 8 8 Adaption to pan-European regulations TBR21,EN301437,TBR38 Current limiter AC impedance, Echo Return Loss Sending and receiving Loudness ratings Sidetone cancellation 8 8 8 8 9 Startup in speech mode 9 CONNECTING A MICROCONTROLLER 9 AS2523/24 BLOCK DIAGRAM 10 Signal truth table AS2523 11 Programming options 11 PROGRAMMING EXAMPLES 14 Going off-hook 14 Generating a flash 14 Generating a dial pulse 14 Muting the transmit and receive path 14 RELATED STANDARDS 15 APPROVALS 15 ORDERING INFORMATION 15 COPYRIGHT 15 CONTACT 16 SALES OFFICES 16 DISTRIBUTORS & REPRESENTATIVES 16 APPLICATION SUPPORT 16 Revision 1.01, Preliminary Page 2 of 16 austriamicrosystems Application Note AN523/24 Other applicable documents and papers General description Data Sheet: AS2523/24 Handsfree Line Interface Circuit Application Notes AN500-x: General analogue telephone IC descriptions Remark: all subsequent component numbering refers to the application schematics, shown in pt. Application Schematic. Getting started Further Applications Applications based on the AS2523/24 are continuously updated. Visit our home-page: http: //www.austriamicrosystems.com - Revision status AS2523/24 Datasheet AN523/24 Application note (this document): DB523/24 Demoboard schematic: DB523/24 Demoboard layout Rev.: Rev.: Rev.: Rev.: 1.9 1.01 A01 A01 Revision history Demoboard and Application note are the first Revision Demo kit contents The available demo-kit DB523/24 contains the following parts: AS2523/24 Single Chip Handsfree Phone Demoboard DB523/24 “ready-to-go” handset handsfree microphone application note AN523/24 AS2523/24 Datasheet Revision 1.01, Preliminary - connect the handset (included in demo kit) to J2 select AC impedance (J23, J7) connect the telephone line connector to J1 connect the handsfree microphone (included in demo kit) to “HF mic”(J4), observe polarity: capsule case is negative terminal for realistic performance check, you may connect an existing handsfree telephone with extended wires from the internal handsfree microphone and loudspeaker connect a 25…32Ω loudspeaker (not included in demo kit) to “Speaker” (J11) select line connector pins on J2,J5 operation in handset mode: activate hookswitch S1 on left upper corner of PCB: depressed position: on-hook, released position: offhook operation in handsfree mode: toggle “h/free”-switch SW2 Remark: The hookswitch and handsfree functionality depends from the controller on the digital interface (J25) - Page 3 of 16 austriamicrosystems Application Note AN523/24 Connector and Jumper locations Listed below are the various connectors and jumpers. The default settings are indicated in bold letters: J1: line connector J2,J5 [3,4]: line input pin selector J11: connect VSS ringer to VSS AS2523/24 [open/closed] J24: VSS test pin J23 [closed],J7[opend]: AC impdeance setting: J3[opend],J13[closed]: enable/disable on-board current limiter C omplex / 600Ω Ω see table LS1: loudspeaker connector J22:[open/closed] enable/disable BNM MIC1: handsfree microphone connector J22: Tone Input connector J25: Connector to controler interface J2: handset connector Figure 1: Connector and Jumper locations Revision 1.01, Preliminary Page 4 of 16 5 - 2 J2 D1 DSS301L RO 3 4 J5 5 - + D2 BRIDGE C 15 replaced with a wire jumper C15 n.c. 2 4 S1 3 6 1 5 7 8 HookSwitch1 4 R10 1M LN_I D3 4004 HS R15 470k D5 4004 HF 1 LS 7 6 8 D4 10V/1W Q1 J3 MPSA92 LN_O U2 HFI HFO OUT Q4 2N5551 R9 10k CTL Q2 MPSA92 R7 100k R16 82k VCC RSL LFI LFO GND R41 390k n.c. J23 n p 3 R11 300R R22 18k Q13 2N5551 n.c. R21 10k R17 2k7 J15 LK_10 X1 R48 18k n.c. 15nF C22 R8 1k8 C12 100uF C26 220nF R32 390k C33 620pF Piezo R5 30R 30 9 12 13 15 C5 10uF C10 1uF 14 22 AS2523/24_sel AS2523/24_sel U1 LS RI 2 LH/HF_Sel TONE IN M3 M1 M4 LI LN_O LN_O RECI LO RECV DI / xPD xCS / xMUTE CLK / HFI TXO TXV Q9 R39 13R 29 28 M4 M3 7 5 RO M2 M1 6 8 17 20 21 23 25 26 27 C31 33uF cw R1 2k2 R2 0R J22 R6 2k R12 8k2 cw P2 25k C21 22nF P3 25k TONE_IN R3 1k2 R13 1k2 R20 680R n.c. C24 1 5 2 C1 220uF R4 1k2 R14 1k2 3 C20 100uF 4 xCS/xMUTE DI/xPD CLK/HFI Header26 2 4 6 8 10 12 14 16 18 20 22 24 26 1 Sheet 1 2 M- LS1 Tele_Hand M+ J4 HF MIC J6 + - 1 LH/HF_SEL TONE_IN Rev A00 VPP 1 D C A AS2523/24_sel B 2 LS2 J8 Speaker J17 J18 LK_10 TIP RING of DET1 J16 LK_10 1 Figure 2: Application Schematic, analog part LH/HF_SEL P1 25k C7 100nF C4 100nF C2 cw 100nF C6 n.c. C8 15nF C9 C11 10nF 15nF J14 LK_10 100nF C13 Rx offset R26 0R C19 22nF J25 1 3 5 7 9 11 13 15 17 19 21 23 25 EC1 EC11 EC12 on the demoboard wired jumpers are used 1nF 1nF 1nF instead of 10R resistors for R29 R46 and R47 Burst protection R29 10R R46 10R R47 10R C23 100uF J9 R49 47k Tuesday, July 15, 2003 Document Number (BGR) austriamicrosystems J21 LK_10 VDD_uC J19 LK_10 HF HS CLK/HFI DI/xPD DPN FCI xCS/xMUTE VDD VSS Size B DB523 Date: Title Disable BNM J13 R43 10k Q12 BC327 C35 10uF/50V R38 1k2 R40 LS 1k2 current limiter for TBR21(optional) C29 C30 22uF 1uF RO M2 AS2523/24 STB CS CI SS VPP VDD C28 100uF BSS92 n.c. Q6 VSS VSSA VPP 11 24 J24 VSS VDD C18 10nF Q10 10 BC327 16 J7 Q11 BC327 C25 470uF D8 1N4148 n.c. C38 22uF n.c. D10 5V1 D12 5V1 n.c. LN_I Hook transistor options: Q7 LN_I2SA1625 n.c. LN_O D11 12V n.c. BC557 2 LINE 2 3 510k 4 5 R42 Sidetone Network J1 Tele_Line C17 + C16 1000pF n.c.1000pF n.c. 2 DPN Rx offset biasing Rx offset CBN 1 SW1 R25 1M C32 100nF R35 TXV TXV 4 D C 1 C36 MOSFET TXO 3 FT1 2 VDD 18 R24 0R wired jumper R23 2k2/0.5W R27 1.5Meg n.c. C27 10uF/50V R36 10k C37 high gain PNP transitor AGND AGND 19 R19 30k n.c. R28 2k2 D7 27V R31 330k J11 4.7nF Aktive HP J12 Tx HP Filter C36 is replaced with a wired jumper on the demoboard J20 LK_10 VDD_uC TXO R44 390k n.c. 3 CTL R30 330k n.c. R34 330k n.c. EC10 390k n.c. CTL BA8206 R18 30k n.c. M3 D6 BRIDGE EC9 4 AGND RING DET1 EC8 n.c. R45 n.c. 1 2 3 4 CAS detection (optional) M2 LA EC7 LB TIP VDD LB 100nF TONE D9 27V n.c. R33 330k n.c. M4 FCI EC6 1nF n.c. C34 10nF n.c. EC5 1nF/250V R37 220k n.c. EC4 1nF 5 LA 1nF/250V C14 680nF/250V 1nF n.c. LINE uC ring detect circuit (optional) EC3 1nF n.c. B A EC2 100nF 1nF M1 Page 5 of 16 Revision 1.01, Preliminary austriamicrosystems Application Note AN523/24 Application Schematic, analog part austriamicrosystems Application Note AN523/24 DB523/24 demoboard: Layout (top view) Figure 3: DB523/24 demoboard: Layout (top view) DB523/24 Demoboard: Component Print Figure 4: DB523/24 Demoboard: Component Print Revision 1.01, Preliminary Page 6 of 16 austriamicrosystems Application Note AN523/24 External component selection Passive components All resistors can be ¼ Watt or less, except: R5 (30Ω) P= I Line ,max ² * 30Ω (e.g. 0.2W @ 80mA) R38 and R40 (each 1k2 / 0.75W; TBR21 application only): The maximum voltage rating for all caps is ≥6V DC, except: C5 (10µ, RI input) 25V C12 (10µ, AC impedance setting) 25V C23 (100µ, speaker decoupling) 16V C6,C7 (0.9µ ringer caps) 160V C35 (10µ, TBR 21 application only) 50V Transistors Most transistors can be general purpose types. Their function and minimum requirements are shown in the table below: Part Nr. Q7(optional) Type on demoboard 2SA 1625K function, minimum requirements pol. PNP hook transistor option: high voltage / high gain equivalent type(s) KSA 1625K V CEO ,V CBO : ≥-200V; hFe ≥100; I C <-100mA Q1,Q2 MPSA 92 PNP hook transistor option: high voltage darlington V CEO ,V CBO : ≥-200V; I C <-100mA Q6 (optional) BSS92 P-Ch hook transistor option: VMOS, MPSA 93, KSP 92/93 BSP 92 (SMD) enhancement V DS ≥-200V , I D <-100mA Q4 2N5551 NPN driver transistor for Q1,Q2 MPSA / KSP 42/43 V CEO ,V CBO : ≥200V IC ≈ 1mA Q10, Q11 BC327-25 PNP line shunt regulation and Vpp supply generation various general purpose.: V CE <-10V , hFe ≥160 I C <-100mA, PD ≤450mW Q13(optional) 2N5551 NPN Q13: ringer startup; generate V DD from ringer signal; if not limited by ext. zener diode after bridge RB2, maximum voltage is the peak ringing voltage. High transient voltages may occur during pulse dialing ( clamped by V1) Q9, Q12 BC557 PNP opt. current limiter general purpose V CE <-10V various BC327-25 PNP opt. current limiter various general purpose V CE <-40V , hFe ≥160 I C <-100mA PD ≤450mW Country specific Settings Some analogue parameters however, require modifications of external passive components. These are: Hardware and software settings AC impedance Most parameters (timings, gains, etc.) can be changed by software via the serial bus interface on AS2523. On AS2524 the gains are fix programmed and can be adjusted over external resistors in an easy way. The internal AC impedance of the chip is 1000Ω./real. By adding a capacitor at pin CI (#16), the synthesized impedance becomes complex (close J7). Revision 1.01, Preliminary Page 7 of 16 austriamicrosystems Application Note AN523/24 A parallel resistor (R8; DC-decoupled by C12) from pin LS (#15) to V SS (#11,) lowers the total AC impedance in the form of a parallel connection between a) the IC’s impedance (1000Ω), b) R9 (typ. 10kΩ) and c) R8: R AC = 1k //R9//R8 Sending and receiving frequency response Although transmit and receive gains can be set by software, additional frequency shaping may be required (depending on acoustic handset characteristics). This can be done by modifying ¯ Example: To set an AC impedance of 600Ω, R8 must be 1,8kΩ (close J23 and open J7): R AC = 1000Ω // 10kΩ // 1k8 = 600Ω Remark: When a MOSFET (optional) hook transistor is used, R9=10kΩ must be excluded from the calculation, because it is not in parallel to the line: gate-source resistance is high ohmic!) On the demoboard, two jumpers, J23 and J7 are provided to quickly change the AC impedance between 600Ω and complex AC impedance. The table printed on the PCB describes the setting: - For 600Ω, close J23 and open J7: R8 is connected to LS and CI is left open For complex impedance, open J23 and close J7: no parallel resistor at LS, C12 connected to CI Sidetone cancellation For sidetone cancellation, a passive complex network (R17,R21,C22) must be connected, which should be 10 times the value of the (complex) line termination for sidetone measurements: - Sidetone network resistor values = 10 times of line termination resistor values Sidetone network capacitor value = 1/10 of line termination capacitor value ¯ ¯ Adaption to pan-European regulations TBR21,EN301437,TBR38 The DB523/24 demoboard can be easily adapted to meet the TBR21/38/EN301437 regulations. The main change is, that a current limiter is required to meet the DC mask requirements for this specification. Current limiter The current limiter must be connected between hook transistor and pin LS (see schematic: optional current limiter). This device is already installed on the demoboard, but can be bypassed with jumper J3 (J13 = open). To activate it, open J3 and close J13. See also for pt. Related Standards links to the European Telecommunications Standards Institute. AC impedance, Echo Return Loss Requirement: The AC impedance must be set to 1000Ω / complex. Echo Return Loss must be ≥14dB @ Z REF (270Ω + 750Ω // 150nF) ⇒ ⇒ Example: for a line termination of 270Ω + 750Ω // 150nF, the equivalent sidetone network would be (R17 + R21 // C22) = 2k7 + 7k5 // 15nF If R8 is installed (e.g. for 600Ω impedance setting), resistor R22 (= 10 times the value of R8) should be connected in parallel to the sidetone network to compensate for the additional load of R8 On the demoboard, an 8-pin DIP socket is provided for the sidetone network to allow easy replacement of the components. Revision 1.01, Preliminary C4, C5, C7, R6 for handsfree sending frequency shaping C8, C9, C11, R25 for handset sending frequency shaping R28, C26...27 for handset receiving frequency shaping remove R8 and C12 (or open J23) and remove R22 short J7 (make sure C18 is 10nF) ⇒ Sending and receiving Loudness ratings Requirement: SLR = +3 ±4dB, RLR = -8 ±4dB With the included handset, the loudness ratings requirements can be met by using the resistor and capacitor values shown in the application schematic. Remark: if necessary, handset Tx and Rx gains can be adjusted by programming on AS2523. On AS2524 gains must be adjusted with resistors. See pt. Signal truth table AS2523. Page 8 of 16 austriamicrosystems Application Note AN523/24 Sidetone cancellation Requirement: Sidetone cancellation is measured with 3 different terminations: a) Zref = 82Ω + 600Ω // 68nF STMR ≥ 5dB b) Zref = 270Ω + 750Ω // 150nF STMR ≥ 10dB c) Zref = 220Ω + 1800Ω // 15nF STMR ≥ 7dB ⇒ Figure 5 and Table XXXX shows the pin description for the DB523/24 digital interface. J25 HF (1) HS (3) CLK/HFI (5) DI/xPD (7) n.c. (9) xCS/xMUTE (11) n.c. (13) VDD (15) n.c. (17) DPN (19) FCI (21) n.c. (23) VSS (25) Good sidetone cancellation is achieved with the installed sidetone network: R17 = 2k7, R21 = 10kΩ, C22 = 15nF, R22=21kΩ some fine tuning may be necessary. Generally, the sidetone network should be 10 X the line termination. R22 is to compensate resistors R9 (10kΩ). Startup in speech mode As soon as either the hookswitch is closed or the handsfree button is pressed, The line transistor is turned on via R15,R16 and Q4. LS is clamped to 10V by the external zener diode D2 and V DD is quickly charged via LI (and an internal path from LI to V DD ). The rising supply voltage generates an internal power-on-reset (POR) on AS2523/24. The POR sets the AS2523/24 into default state (see pt. Signal truth table AS2523 default settings). The first job for the controller is to detect the hook event and hold the hook transistor in off-hook state by turning pin 19 (DPN on controller interface jumper J25) on. This is necessary because in case the handsfree button was pressed, it would only turn Q4 ON, while it is closed. Therefore DPN must go HIGH, before the handsfree button is released again. The hookswitch (SW1) on the other hand, would always keep Q4 ON, as long as it is offhook (=closed). Next, depending on hook event, the AS2523 must be set to the corresponding speech mode (handset mode, handsfree mode) by sending the proper command (“D4“ for handset mode, “D6” for handsfree mode) to the serial bus. Remark: Per default the AS2523 is set into handset mode after a POR. The AS2523 serial interface will accept commands, as soon as V DD is powered up. (2) AS2523/24_sel (4) (6) n.c. (8) n.c. (10) TONE (12) n.c. (14) n.c. (16) (18) RING (20) n.c. (22) DET1 (24) n.c. (26) Figure 5: Controller interface on DB523/24 Pin Nr. Pin Name description 1 HF 2 AS2523/24_sel Selector for AS2523/24 (only for COB) Handsfree hook signal 3 HS Handset hook signal 4 LH/HF_Sel Selector for Loudhearing or Handsfree (only for COB) 5 CLK/HFI CLK clock signal on AS2523 HFI Handsfree pin on AS2524 6 n.c. not connected 7 DI/xPD DI Data input on AS2523 xPD Power down pin on AS2524 8 n.c. not connected 9 n.c. not connected 10 TONE IN Analog tone input forDTMF, FSK .. Signals 11 xCS/xMUTE xCS Chip select on AS2523 xMute pin on AS2524 12 n.c. not connected 13 n.c. not connected 14 n.c. not connected 15 VDD Supply voltage analog 16 TIP for CID (optional) 17 n.c. not connected 18 RING for CID (optional) 19 DPN Connecting a Microcontroller 20 n.c. not connected 21 FCI Ring frequency detetcion (optional) One of the major benefits, when using AS2523 is, that it can be interfaced with almost any microcontroller. For the serial interface only 3 signals are necessary to control the AS2523: Chip Select, Clock and Data In. The digital interface on the Demoboard DB523/24 provides the most common signals, which are required for an analog telephone design. 22 DET1 for CID (optional) 23 n.c. not connected 24 n.c. not connected 25 VSS Common ground VPP Supply voltage Revision 1.01, Preliminary 26 Table 1: Pin description controller interface Page 9 of 16 austriamicrosystems Application Note AN523/24 AS2523/24 Block Diagram Figure 5: AS2523/24 Block Diagram Revision 1.01, Preliminary Page 10 of 16 austriamicrosystems Application Note AN523/24 Signal truth table AS2523 CS CLK ↓ A3 DI (from µC) ↓ A2 ↓ A1 ↓ A0 ↓ D3 ↓ D2 ↓ D1 ↓ D0 For programming the AS2523, three signals are required: Chip Select (XCS), Clock (CLK), and Data In (DI). The falling edge of CS enables the internal shift register. Data at DI is read with every rising edge of CLK, A3 must be clocked in first, D0 is last. After 8 clock pulses, CS should be pulled high. With the rising edge of CS, the shift register data is sent to the internal registers. Programming options Each command consists of a 4-bit address and 4 bit data. The following commands are possible: Command [Hex] A3 A2 A1 A0 D3 D2 D1 D0 Default settings are shown in D 3 ...D 0 and in bold letters: 0x 0 0 0 0 X x X x Not used 1x 0 0 0 1 X X X X Not used 2x 0 0 1 0 X X X X Not used 3x 0 0 1 1 x X x X Not used A0 0 Confidence Tone, DC-mask, Line Loss Compensation Co = Confidence tone: [0]= off, [1]= on L = LI-Voltage: [0]= 3,5V, [1]= 4,5V A 1 ,A 0 : 11= 01 = noLLC, 00= LO (20-50mA), 10= HI (45-75mA) 40...4F 50...5F 0 0 1 1 0 0 0 Co 0 Liv 0 A BR A BS 0 Revision 1.01, Preliminary 1 1 C1 C0 0 T1 1 0 T0 0 0 SR 0 Analog Tone confidence tone level: AB R : Tone is sent to receiver (RO) : on[1] / off[0] AB S : Tone is sent to Speaker (LO) : on[1] / off[0] 1 C 1 /C 0 : confidence tone level @RO /LO1,2 rel. to LS: 00 = -36dB -15dB 01 = -30dB -9dB 10 = -24dB -3dB 11 = -18dB +3dB ST 0 Transmit comperator gain and soft clipping: T 1 /T 0 : Tx comperator gain settings for Handsfree adjustment 00 = +8dB 01 = +11dB 10 = +14dB 11 = +17dB S R : Soft clipping at RO: on[1] / off[0] S T : Soft clipping at LS: on[1] / off[0] 1 0 60...6F A1 0 Page 11 of 16 austriamicrosystems Application Note AN523/24 Command [Hex] 70...7F 80...8F A3 0 1 A2 1 0 A1 1 0 A0 D3 D2 D1 D0 R1 R0 D B 0 0 1 1 X 1 X 0 x 1 x 1 1 0 Default settings areshown in D 3 ...D 0 and in bold letters: Rx- DC offset, Switching delay and Noise monitoring: R 1 /R 0 : Rx DC offset: 00 = 0mV 01 = 12mV 10 = 40mV 11 = 120mV D: 10ms switching delay: on[1] / off[0] B: Handsfree Background noise monitoring: on[1] / off[0] Handsfree receive end gain; speaker volume [1011] 16 steps, total attenuation range = -20dB: 0000=min Vol; Rx gain = -20dB; Tx gain = -30dB 1111=max Vol; Rx gain = 0dB; Tx gain = -50dB Handsfree voice switching speed 1/2/4/8x: S 1 ,S 0 : 00 ≈ 1ms / 6dB (maximum speed ) 01 ≈ 2ms / 6dB 10 ≈ 4ms / 6dB 90...93 1 0 0 1 O1 1 O0 0 S1 0 S0 0 11 ≈ 8ms / 6dB (minimum speed) with BNM on, switching from Tx->idle, Rx->idle is ≈30/60/120/240 ms/6dB respectively O 0 ,O 1 Background Noise Monitor Offset O1 0 0 1 1 A0...AF 1 Revision 1.01, Preliminary 0 1 0 O0 0 1 0 1 BGN-offset 120mV 180mV 240mV 300mV T3 T2 T1 T0 Transmit gain [0111] 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 Data[Hex] 0 1 2 3 4 5 6 7 8 9 A B C D E F Handset mode 30dB 31dB 32dB 33dB 34dB 35dB 36dB 37dB 38dB 39dB 40dB 41dB 42dB 43dB 44dB 45dB Handsfree mode 39dB 40dB 41dB 42dB 43dB 44dB 45dB 46dB 47dB 48dB 49dB 50dB 51dB 52dB 53dB 54dB Page 12 of 16 austriamicrosystems Application Note AN523/24 Command [Hex] A3 A2 A1 A0 D3 D2 D1 D0 Default settings areshown in D 3 ...D 0 and in bold letters: R3 R2 R1 R0 Receive gain [0111] Data[Hex] B0...BF C0...C7 D0...DF 1 1 1 0 1 1 1 0 0 1 0 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 H 0 M 0 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 R 1 S2 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 M 0 S1 0 handset mode: LS->RO -6dB -5dB -4dB -3dB -2dB -1dB 0dB 1dB 2dB 3dB 4dB 5dB 6dB 7dB 8dB 9dB handsfree mode: LS->LO1/2@max vol. 22dB 23dB 24dB 25dB 26dB 27dB 28dB 29dB 30dB 31dB 32dB 33dB 34dB 35dB 36dB 37dB 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 2 3 4 5 6 7 8 9 A B C D E F T 0 High pass for loudhearing , Receive comperator, Mute, Tone: H: High pass cut off frequency: 200Hz [1] / 2000Hz[0] R: Signal to Rx comperator : on[1] / off[0] M: Mute: on[1] / off[0] T: Tx signal path: Tone in signal path[1] / Tx signal path on[0] S0 0 Mask Bit, Speech modes: S 2 ,S 1 ,S 0 : M: Maske:[0]: normal [1]: power save; LI Forced to 0.7V(for LD dialing) S 2 ,S 1 ,S 0 , Speech modes: 0xx = power down, no line regulation 100 = Handset mode 101 = not allowed 110 = Handsfree mode 111 = Loudhearing mode E0...EF 1 1 1 0 K5 K3 K2 S S Only for the loudhearing mode! S: [0]:Normal voice switching speed [1]:fast change to TX, slow change to Rx, no IDLE S 2 ,S 1 ,S 0 for factory testing only [0000] Fx 1 1 1 1 X x x x Reset to default settings Revision 1.01, Preliminary Page 13 of 16 Application Note AN523/24 austriamicrosystems Programming examples Generating a dial pulse The following examples give some guidelines on how to perform specific functions when using the AS2523 in a system design. All commands, addresses and data are in Hex-numbers, component numbers refer to the DB523/24 schematic in pt.Application Schematic, analog part: The break-period of a dial pulse is generated in the same way as a flash (see pt. Generating a flash), the makeperiod is generated by turning the hook transistor on while leaving the AS2523 in the power-save mode (MASK-bit = 1). In power-save, LI is pulled down to 1.2V, resulting in a low DC-resistance at the tip/ring terminals during the make-period. Going off-hook After power up (close hookswitch & apply line current), the AS2523 line regulation is active (see defaults Addr. D). The first command must therefore set the AS2523 in the detected speech mode: command = D4 for handset mode, D6 for handsfree mode D7 for loudhearing mode Afterwards, if necessary, the other parameters, like DCmask, Line loss compensation, Tx-Rx gains and soft clipping can be sent. For handsfree operation, voice switching speed, speaker volume and background noise monitoring can be selected. Muting the transmit and receive path The receive path can be muted by setting bit M of addr. C.: There is no dedicated mute-bit for the transmit path, but you may mute the transmit path by switching to Tone In mode while there is no tone applied at the tone pin: command = C1 (Tone path = on). Generating a flash A flash is a timed interruption of the line, consequently it must be performed by turning off the hook transistor during the flash (Q1, via Q4). However, as soon ad the hook transistor is turned off, there is no more line current available to support the ICs. Therefore, V DD must be supplied from the buffer capacitor (C10). To avoid fast discharge of the V DD buffer cap by high supply current during the flash, the AS2523 shall be switched to a powersave mode: command = DC (MASK-bit = 1). Revision No.1.01, Date November 2003 Page 14 of 16 austriamicrosystems Application Note AN523/24 Related Standards The product, AS25xx, is designed to be in compliance with ETSI standards for connection to the analogue PSTN of terminal equipment including voice telephony services or other voice band communication when installed into a properly designed system. The specification of the product is based on following standards and requirements: NET 4 ETS 300 001, PSTN basic access; analogue terminal equipment general requirements, March 1996. EN55022 EMC ( Electro Magnetic Compatibility) IEC 1000-4-3 Electromagnetic Irradiation (CE approval) TBR 21 pan-European approval for connection to the analogue Public Switched Telephone Network (line interface part) TBR 38 pan-European approval for connection to the analogue Public Switched Telephone Network (acoustics). See http://www.etsi.org for further information Note: Some national PTT authorities may have additional requirements exceeding the above standards and requirements. Such additional requirements have only been respected to the extent that they were known to austriamicrosystems prior to designing the product. However, austriamicrosystems shall not be liable to recipient or any third party in connection with the approval procedures of applications in which the AS25xx is used. specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for each application. Copyright Copyright © 1999, austriamicrosystems AG, Schloss Premstaetten, A-8141 Unterpremstaetten, Austria-Europe. Trademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However, austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystems AG rendering of technical or other services. Approvals Since the AS25xx is a component and not a complete system, it can not be approved as a stand alone part by the standards bodies. Hence, full conformance to above standards is depending on the application in which the AS25xx is being used, and therefore, approvals by the standards bodies are the responsibility of the customer and austriamicrosystems will not have tested the product to meet the above standards. Ordering information Devices sold by austriamicrosystems AG are covered by the warranty and patent identification provisions appearing in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. austriamicrosystems AG reserves the right to change Revision No.1.01, Date November 2003 Page 15 of 16 austriamicrosystems Application Note AN523/24 Contact Headquarters austriamicrosystems AG accento! Business Unit Communications A 8141 Schloss Premstätten, Austria T. +43 (0) 3136 500 0 F. +43 (0) 3136 525 01 [email protected] www.austriamicrosystems.com USA (west) austriamicrosystems USA, Inc. Suite 116, 4030 Moorpark Ave, San Jose, CA 95117, USA Phone: +1/408/345 1790 Fax: +1/408/345 1795 USA (east) Sales Offices austriamicrosystems USA, Inc. Suite 300, 4030 Wake Forest Road Raleigh, NC 27609, USA Phone: +1/919/719 7214 Fax: +1/919/719 2799 Germany United Kingdom austriamicrosystems Germany GmbH Tegernseer Landstrasse 85 D-81539 München, Germany Phone: +49/89/693643-0 Fax: +49/89/693643-66 austriamicrosystems UK, Ltd. Coliseum Business Centre, Watchmoor Park Camberley, Surrey, GU15 3YL, UK Phone: +44/1276/23 3 99 Fax: +44/1276/29 3 53 France austriamicrosystems France S.a.r.l. 124, Avenue de Paris F-94300 Vincennes, France Phone: +33/1/43 74 00 90 Fax: +33/1/43 74 20 98 Italy austriamicrosystems Italy S.r.l. Via Leone Tolstoi, 64 I-20146 Milano, Italy Phone: +39/0242/36713 Fax: +39/0242/290889 Switzerland austriamicrosystems Switzerland AG Rietstrasse 4 CH-8640 Rapperswil, Switzerland Phone: +41/55/220 9000 Fax: +41/55/220 9001 Revision No.1.01, Date November 2003 Japan austriamicrosystems AG Shin Yokohama Daini, Center Bldg. 10F 3-19-5, Shin Yokohama Kohoku-ku, Yokohama 222-0033, Japan Phone: +81/45/474 0962 Fax: +81/45/472 9845 Distributors & Representatives austriamicrosystems AG is represented by distributors in the following countries. Please contact your nearest regional sales office for the distributor address: Spain, Israel, Korea, Hong-Kong, Taiwan, Malaysia, Singapur, India, Brazil Application Support Please contact your local sales office or your distributor. Page 16 of 16