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TIME SLOT INTERCHANGE DIGITAL SWITCH 128 x 128
.EATURES:
* * * * * * * * *
IDT728981
128 x 128 channel non-blocking switch Serial Telecom Bus Compatible (ST-BUS(R)) 4 RX inputs--32 channels at 64 Kbit/s per serial line 4 TX output--32 channels at 64 Kbit/s per serial line Three-state serial outputs Microprocessor Interface (8-bit data bus) 5V Power Supply Available in 44-pin Plastic Leaded Chip Carrier (PLCC), 40-pin Plastic Dip (P-DIP) and 44-pin Plastic Quad Flatpack (PQFP) Operating Temperature Range -40C to +85C
outputs, each of which consists of 32 channels (64 Kbit/s per channel) to form a multiplexed 2.048 Mb/s stream.
.UNCTIONAL DESCRIPTION
A functional block diagram of the IDT728981 device is shown below. The serial streams operate continuously at 2.048 Mb/s and are arranged in 125s wide frames each containing 32, 8-bit channels. Four input (RX0-3) and four output (TX0-3) serial streams are provided in the IDT728981 device allowing a complete 128 x 128 channel non-blocking switch matrix to be constructed. The serial interface (C4i) clock for the device is 4.096 MHz. The received serial data is internally converted to a parallel format by the on chip serial-to-parallel converters and stored sequentially in a 128-position Data Memory. By using an internal counter that is reset by the input 8 KHz frame pulse, F0i, the incoming serial data streams can be framed and sequentially addressed.
DESCRIPTION:
The IDT728981 is a ST-BUS(R) compatible digital switch controlled by a microprocessor. The IDT728981 can handle as many as 128, 64 Kbit/s input and output channels. Those 128 channels are divided into 4 serial inputs and
.UNCTIONAL BLOCK DIAGRAM
C4i
F0i
VCC
GND
ODE
Timing Unit
RX0 RX1 RX2 RX3
Output MUX
TX0
Receive Serial Data Streams
Data Memory Control Register Connection Memory
Transmit Serial Data Streams
TX1 TX2 TX3
Microprocessor Interface
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DS CS R/W A0/ DTA D0/ A5 D7
JANUARY 2001
1
2001 Integrated Device Technology, Inc. DSC-5703/1
IDT728981 Time Slot Interchange Digital Switch 128 x 128
Commercial Temperature Range
PIN CON.IGURATION
DTA DNC(1)
DNC(1)
DNC(1)
DNC(1)
DNC(1)
ODE
RX1
DTA
RX2
RX0
ODE TX0
RX0
RX1
TX0
TX1
TX2
INDEX
INDEX
44
41
39
43
42
38
40
37
36
2
35
44
43
42
41
RX3 VCC VCC VCC VCC VCC F0i C4i A0 A1 A2
1
40
7 8 9 10 11 12 13 14 15 16 17
21 20 22
39 38 37 36 35 34 33 32 31 30 29
TX3 DNC(1) DNC(1) DNC(1) DNC(1) GND D0 D1 D2 D3 D4
RX3 VCC VCC VCC VCC VCC F0i C4i A0 A1 A2
34
6
4
5
3
DNC(1)
RX2
TX1
TX2
1 2 3 4 5 6 7 8 9 10 11
12 15 17 13 14 18 16 19 20 21 22
33 32 31 30 29 28 27 26 25 24 23
TX3 DNC(1) DNC(1) DNC(1) DNC(1) GND D0 D1 D2 D3 D4
23
24
25
26
18
19
27
28
DTA
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21
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DNC(1)
CS D7 D6 DNC(1) DS R/W D5 A3 A4 A5 DNC(1)
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DNC(1)
DNC(1)
D7
D6
DS
R/W
CS
D5
A3
A4
A5
RX0 RX1 RX2
ODE TX0 TX1 TX2 TX3 DNC(1) DNC(1) DNC(1) DNC(1) GND D0 D1 D2 D3 D4 D5 D6 D7 CS
PLCC: 0.05in. pitch, 0.65in. x 0.65in. (J44-1, order code: J) TOP VIEW
RX3 VCC VCC VCC VCC VCC F0i C4i A0 A1 A2
PQFP: 0.80mm pitch, 10mm x 10mm (DB44-1, order code: DB) TOP VIEW
NOTE: 1. DNC - Do Not Connect
A3 A4 A5 DS R/W
PIN DESCRIPTIONS
SYMBOL
GND VCC
PLASTIC DIP: 0.10in. pitch, 2.05in. x 0.60in. (P40-1, order code: P) TOP VIEW
NAME
Ground. VCC Data Acknowledgment (Open Drain) RX Input 0 to 3 Frame Pulse Clock Address 0 to 5 Data Strobe Read/Write Chip Select Data Bus 0 to 7 TX Outputs 0 to 3 (Three-state Outputs) Output Drive Enable
I/O
DESCRIPTION
Ground Rail. +5.0 Volt Power Supply. This active LOW output indicates that a data bus transfer is complete. A pull-up resistor is required at this output. Serial data input streams. These streams have 32 channels at data rates of 2.048 Mb/s. This input identifies frame synchronization signals formatted to ST-BUS(R) specifications. 4.096 MHz serial clock for shifting data in and out of the data streams. These lines provide the address to IDT728981 internal registers. This is the input for the active HIGH data strobe on the microprocessor interface. This input operates with CS to enable the internal read and write generation. This input controls the direction of the data bus lines (D0-D7) during a microprocessor access. Active LOW input enabling a microprocessor read or write of control register or internal memories. These pins provide microprocessor access to data in the internal control register. Connection Memory HIGH, Connection Memory LOW and data memory. Serial data output streams. These streams are composed of 32, 64 Kbit/s channels at data rates of 2.048 Mb/s. This is an output enable for the TX0-3 serial outputs. If this input is LOW, TX0-3 are high-impedance. If this is HIGH, each channel may still be put into high-impedance by software control.
2
DTA
RX0-3
O I I I I I I I I/O O I
F0i C4i
A0-A5 DS R/W
CS
D0-D7 TX0-3 ODE
IDT728981 Time Slot Interchange Digital Switch 128 x 128
Commercial Temperature Range modes such as: Processor mode or Connection mode and Output Drivers Enabled or in three-state condition. OUTPUT DRIVE ENABLE (ODE) The ODE pin is the master three-state output control pin. If the ODE input is held LOW all TX outputs will be placed in high impedance regardless Connection Memory High programming. However, if ODE is HIGH, the contents of Connection Memory High control the output state on a per-channel basis. DELAY THROUGH THE IDT728981 The transfer of information from the input serial streams to the output serial streams results in a delay through the device. The delay through the IDT728981 device varies according to the combination of input and output streams and the movement within the stream from channel to channel. Data received on an input stream must first be stored in Data Memory before it is sent out. As information enters the IDT728981 it must first pass through an internal serial-to-parallel converter. Likewise, before data leaves the device, it must pass through the internal parallel-to-serial converter. This data preparation has an effect on the channel positioning in the frame immediately following the incoming frame--mainly, data cannot leave in the same time slot. Therefore, information that is to be output in the same channel position as the information is input, relative to the frame pulse, will be output in the following frame. Whether information can be output during a following timeslot after the information entered the IDT728981 depends on which RX stream the channel information enters on and which TX stream the information leaves on. This is caused by the order in which input stream information is placed into Data Memory and the order in which stream information is queued for output. Table 1 shows the allowable input/output stream combinations for the minimum two channel delay.
.UNCTIONAL DESCRIPTION (Cont'd)
Data to be output on the serial streams may come from two sources: Data Memory or Connection Memory. The Connection Memory is 16 bits wide and is split into two 8-bit blocks--Connection Memory HIGH and Connection Memory LOW. Each location in Connection Memory is associated with a particular channel in an output stream so as to provide a one-to-one correspondence between Connection and Data Memories. This correspondence allows for per channel control for each TX output stream. In Processor Mode, data output on the TX is taken from the Connection Memory Low and originates from the microprocessor (Figure 2). Where as in Connection Mode (Figure 1), data is read from Data Memory using the address in Connection Memory. Data destined for a particular channel on the serial output stream is read during the previous channel time slot to allow time for memory access and internal parallel-to-serial conversion. CONNECTION MODE In Connection Mode, the addresses of input source for all output channels are stored in the Connection Memory Low. The Connection Memory Low locations are mapped to corresponding 8-bit x 32-channel output. The contents of the Data Memory at the selected address are then transferred to the parallelto-serial converters. By having the output channel to specify the input channel through the Connection Memory, input channels can be broadcast to several output channels. PROCESSOR MODE In Processor Mode the CPU writes data to specific Connection Memory Low locations which are to be output on the TX streams. The contents of the Connection Memory Low are transferred to the parallel-to-serial converter one channel before it is to be output and are transmitted each frame to the output until it is changed by the CPU. CONTROL The Connection Memory High bits (Table 4) control the per-channel functions available in the IDT728981. Output channels are selected into specific
Input 0 1
Output Stream 1,2,3 3
RX
Receive Serial Data Streams
Data Memory Connection Memory
Table 1. Input Stream to Output Stream Combinations that can Provide the Minimum 2-Channel Delay
Transmit Serial Data Streams
TX
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Figure 1. Connection Mode
A5 A4 A3 A2 A1 A0 0 1 1 1 * 1 1 X 0 0
* * *
HEX ADDRESS 00-1F 20 21
* * *
LOCATION Control Register(1) Channel 0(2) Channel 1(2)
* * *
X 0 0
* * *
X 0 0
* * *
0 0 0
* * *
0 0 1
* * *
Receive Serial Data Streams
Data Memory Connection Memory
Transmit Serial Data Streams
TX
1
1
1
1
1
3F
Channel 31(2)
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Microprocessor
NOTES: 1. Writing to the Control Register is the only fast transaction. 2. Memory and stream are specified by the contents of the Control Register. Table 2. Address Mapping
Figure 2. Processor Mode
3
IDT728981 Time Slot Interchange Digital Switch 128 x 128
Commercial Temperature Range If PE is LOW, then bit 2 and 0 of each Connection Memory High location operates normally. In this case, if bit 2 of the CMH is HIGH, the associated TX output channel is in Processor Mode. If bit 2 of the CMH is LOW, then the contents of the CML define the source information (stream and channel) of the time slot that is to be switched to an output. If the ODE input pin is LOW, then all the serial outputs are high-impedance. If ODE is HIGH, then bit 0 (Output Enable) of the CMH location enables (if HIGH) or disables (if LOW) the output stream and channel. INITIALIZATION OF THE IDT728981 On initialization or power up, the contents of the Connection Memory High can be in any state. This is a potentially hazardous condition when multiple TX outputs are tied together to form matrices. The ODE pin should be held low on power up to keep all outputs in the high impedance condition until the contents of the CMH are programmed. During the microprocessor initialization routine, the microprocessor should program the desired active paths through the matrices, and put all other channels into the high impedance state. Care should be taken that no two connected TX outputs drive the bus simultaneously. With the CMH setup, the microprocessor controlling the matrices can bring the ODE signal high to relinquish high impedance state control to the Connection Memory High bits outputs.
SO.TWARE CONTROL
If the A5 address line input is LOW then the IDT728981 Internal Control Register is addressed. If A5 input line is high, then the remaining address input lines are used to select the 32 possible channels per input or output stream. The address input lines and the Stream Address bits (STA) of the Control register give the user the capability of selecting all positions of IDT728981 Data and Connection memories. The IDT728981 memory mapping is illustrated in Table 2 and Figure 3. The data in the control register (Table 3) consists of Memory Select and Stream Address bits, Split Memory and Processor Mode bits. In Split Memory mode (Bit 7 of the Control register) reads are from the Data Memory and writes are to the Connection Memory as specified by the Memory Select Bits (Bits 4 and 3 of the Control Register). The Memory Select bits allow the Connection Memory HIGH or LOW or the Data Memory to be chosen, and the Stream Address bits define internal memory subsections corresponding to input or output streams. The Processor Enable bit (bit 6) places EVERY output channel on every output stream in Processor mode; i.e., the contents of the Connection Memory LOW (CML, see Table 5)) are output on the TX output streams once every frame unless the ODE input pin is LOW. If PE bit is HIGH, then the IDT728981 behaves as if bits 2 (Channel Source) and 0 (Output Enable) of every Connection Memory High (CMH) locations were set to HIGH, regardless of the actual value.
Control Register
CRb7
CRb6
CRb5
CRb4
CRb3
CRb2
CRb1
CRb0
The Control Register is only accessed when A5=0. All other address bits have no effect when A5=0. When A5 =1, only 32 bytes are randomly accessable via A0-A4 at any one instant. Which 32 bytes are accessed is determined by the state of CRb0 -CRb4. The 32 bytes correlate to 32 channel of one ST-BUS stream.
CRb4 0 1 1
CRb3 1 0 1
Connection Memory High Connection Memory Low
Data Memory
Channel 0 Channel 0 Channel 0 Channel 0 Channel 1 Channel 1 Channel 1 Channel 1 Channel 2 Channel 2 Channel 2 Channel 2 Channel 31 Channel 31 Channel 31 Channel 31
CRb1
0 0 1 1
CRb0 Stream
0 1 0 1 0 1 2 3
100000
100001
100010
111111
External Address Bits
A5-A0
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Figure 3. Address Mapping
4
IDT728981 Time Slot Interchange Digital Switch 128 x 128
Commercial Temperature Range
Mode Control Bits
(unused)
Memory Select Stream Address Bits (unused) Bits
7
6
5
4
3
2
1
0
Bit
7
Name
SM (Split Memory)
Description
When 1, all subsequent reads are from the Data Memory and writes are to the Connection Memory LOW, except when the Control Register is accessed again. When 0, the Memory Select bits specify the memory for the operations. In either case, the Stream Address Bits select the subsection of the memory which is made available. When 1, the contents of the Connection Memory LOW are output on the Serial Output streams except when the ODE pin is LOW. When 0, the Connection Memory bits for each channel determine what is output. unused 0-0 - Not to be used. 0-1 - Data Memory (read only from the microprocessor port) 1-0 - Connection Memory LOW 1-1 - Connection Memory is HIGH unused The number expressed in binary notation on these bits refers to the input or output stream which corresponds to the subsection of memory made accessible for subsequent operations.
Table 3. Control Register Configuration
6 5 4-3
PE (Processor Mode)
MS1-MS0 (Memory Select Bits)
2 1-0 STA1-0 (Stream Address Bits)
No Corresponding Memory - These bits give 0s if read
CS
(unused)
OE
7
6
5
4
3
2
1
0
Bit
2
Name
CS (Channel Source)
Description
When 1, the contents of the corresponding location in Connection Memory LOW are output on the location's channel and stream. When 0, the contents of the corresponding location in Connection Memory LOW act as an address for the Data Memory and determine the source of the connection to the location's channel and stream. unused If the ODE pin is HIGH and bit 6 of the Control Register is 0, then this bit enables the output driver for the location's channel and stream. This allows individuals channels on individuals streams to be made high-impedance, allowing switching matrices to be constructed. A 1 enables the driver and a 0 disables it.
Table 4. Connection Memory High Register
1 0 OE (Output Enable)
(unused)
Stream Address Bits
Channel Address Bits
7
6
5
4
3
2
1
0
Bit
7
Name
unused
Description
The number expressed in binary notation on these 2 bits are the number of the stream for the source of the connection. Bit 6 is the most significant bit, e.g., If bit 6 is 1, bit 5 is 0 then the source of the connection is a channel on RX2. The number expressed in binary notation on these 5 bits is the number of the channel which is the source of the connection (the stream where the channel lies is defined by bits 7, 6 and 5). Bit 4 is the most significant bit, e.g., if bit 4 is 1, bit 3 is 0, bit 2 is 0, bit 1 is 1 and bit 0 is 1, then the source of the connection is channel 19.
6-5(1) Stream Address Bits 4-0(1) Channel Address Bits
NOTE: 1. If bit 2 of the corresponding Connection HIGH location is 1 or bit 6 of the Control Register is 1, then these entire 8 bits are output on the channel and stream associated with this location. Otherwise, the bits are used as indicated to define the source of the connection which is output on the channel and stream associated with this location. Table 5. Connection Memory Low Register
5
IDT728981 Time Slot Interchange Digital Switch 128 x 128
Commercial Temperature Range
(1)
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter VCC - GND Vi VO IO TS PD Voltage on Digital Inputs Voltage on Digital Outputs Current at Digital Outputs Storage Temperature Package Power Dissapation -65 Min. -0.3 GND - 0.3 GND - 0.3 Max. 7
Unit V V V mA C W
RECOMMENDED OPERATING CONDITIONS
Symbol VCC VI TOP Parameter Positive Supply Input Voltage Operating Temperature Commercial Min. 4.75 0 -40 Typ.(1) Max. 5.25 VCC +85 Unit V V C
VCC +0.3 VCC +0.3 40 +150 2
NOTE: 1. Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied.
NOTE: 1. Typical figures are at 25C and are for design aid only; not guaranteed and not subject to production testing.
DC ELECTRICAL CHARACTERISTICS
Symbol ICC VIH VIL IIL CI VOH IOH VOL IOL IOZ CO Parameter Supply Current Input High Voltage Input Low Voltage Input Leakage Input Capacitance Output High Voltage Output High Current Output Low Voltage Output Low Current High Impedance Leakage Output Pin Capacitance Min. 2.0 2.4 10 5 Typ.(1) 7 8 15 10 8 Max. 10 0.8 5 0.4 5 Units mA V V A pF V mA V mA A pF IOH = 10mA Sourcing. VOH = 2.4V IOL = 5mA Sinking. VOL = 0.4V VO between GND and VCC VI between GND and VCC Test Conditions Outputs Unloaded
NOTE: 1. Typical figures are at 25C and are for design aid only; not guaranteed and not subject to production testing.
Test Point
VCC
Output Pin S1 CL GND
RL S2 GND
S1 is open circuit except when testing output levels or high impedance states. S2 is switched to VCC or GND when testing output levels or high impedance states.
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Figure 4. Output Load
6
IDT728981 Time Slot Interchange Digital Switch 128 x 128
Commercial Temperature Range
(1)
AC ELECTRICAL CHARACTERISTICS
Symbol tCLK tCH tCL tCTT tFPS tFPH tFPW Characteristics Clock Period(3) Clock Width High Clock Width Low Clock Transition Time Frame Pulse Setup Time Frame Pulse Hold Time Frame Pulse Width Min. 220 95 110 20 0.020
CLOCK TIMING
Max. 300 150 150 200 50 Unit ns ns ns ns ns s ns 244 122 122 20 244
Typ.(2)
NOTE: 1. Timing is over recommended temperature and power supply voltages. 2. Typical figures are at 25C and are for design aid only; not guaranteed and not subject to production testing. 3. Contents of Connection Memory are not lost if the clock stops, however, TX outputs go into the high impedance state.
C4i
F0i
Bit Cells
Channel 31 Bit 0
Channel 0 Bit 7
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Figure 5. Frame Alignment
tCLK tCTT tCL
C4i
tCTT tCHL
(( ))
tCH
tFPH
F0i
tFPS tFPW
tFPH
tFPS
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Figure 6. Clock Timing
7
IDT728981 Time Slot Interchange Digital Switch 128 x 128
Commercial Temperature Range
(1)
AC ELECTRICAL CHARACTERISTICS
Symbol tTAZ tTZA tTAA tTOH tOED tSIS tSIH Characteristics TX0-3 Delay - Active to High Z TX0-3 Delay - High Z to Active TX0-3 Delay - Active to Active TX0-3 Hold Time Output Driver Enable Delay Serial Input Setup Time Serial Input Hold Time Min. 20 25 30 25 90
SERIAL STREAM TIMING
Max. 60 70 70 70 -20 Unit ns ns ns ns ns ns ns Test Conditions RL = 1K(3), CL = 150pF CL = 150pF CL = 150pF CL = 150pF RL = 1K(3), CL = 150pF 30 45 45 45 -40
Typ.(2)
NOTE: 1. Timing is over recommended temperature and power supply voltages. 2. Typical figures are at 25C and are for design aid only; not guaranteed and not subject to production testing. 3. High Impedance is measured by pulling to the appropriate rail with RL, with timing corrected to cancel time taken to discharge CL.
ODE
Bit Cell Boundary
tOED
tOED
TX0-3
C4i
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tTAZ tTOH TX0-3
Figure 8. Output Driver Enable
tTZA
Bit Cell Boundaries
TX0-3
C4i
tTAA tTOH TX0-3
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tSIS
tSIH
RX0-3
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Figure 7. Serial Outputs and External Control
Figure 9. Serial Inputs
8
IDT728981 Time Slot Interchange Digital Switch 128 x 128
Commercial Temperature Range
(1)
AC ELECTRICAL CHARACTERISTICS
Symbol tCSS tRWS tADS tAKD tAKD tFWS tSWD tRDS tDHT tDHT tRDZ tCSH tRWH tADH tAKH Characteristics Chip Select Setup Time Read/Write Setup Time Address Setup Time Acknowledgment Delay Fast Acknowledgment Delay Slow Fast Write Data Setup Time Slow Write Data Delay Read Data Setup Time Data Hold Time Read Data Hold Time Write Read Data to High Impedance Chip Select Hold Time Read/Write Hold Time Address Hold Time Acknowledgment Hold Time Min. 10 10 10 2.7 20 20 20 0 0 0 10
PROCESSOR BUS
Typ.(2) 0 30 2.0 10 30 20 Max. 60 7.2 1.7 0.5 60 40 Unit ns ns ns ns cycles ns cycles cycles ns ns ns ns ns ns ns RL = 1K(3), CL = 150pF RL = 1K(3), CL = 150pF C4i cycles C4i cycles, CL = 150pF RL = 1K(3), CL = 150pF CL = 150pF C4i cycles(4) Test Conditions
NOTE: 1. Timing is over recommended temperature and power supply voltages. 2. Typical figures are at 25C and are for design aid only; not guaranteed and not subject to production testing. 3. High Impedance is measured by pulling to the appropriate rail with RL, with timing corrected to cancel time taken to discharge CL. 4. Processor accesses are dependent on the C4i clock, and so some things are expressed as multiples of the C4i.
DS tCSS CS tRWS R/W tRWH tCSH
tADS A5-A0 tAKD DTA tRDS tSWD D7-D0 tFWS
tADH
tAKH
tRDZ tDHT
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Figure 10. Processor Bus
9
ORDERING IN.ORMATION
IDT XXXXXX Device Type XX Package X Process/ Temperature Range BLANK Commercial (-40C to +85C)
J P DB
Plastic Leaded Chip Carrier (PLCC, J44-1) Plastic Dip (P40-1) Plastic Quad Flatpack (PQFP, DB44-1)
728981
128 x 128 Time Slot Interchange Digital Switch
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DATASHEET DOCUMENT HISTORY
5/23/2000 8/18/2000 01/24/2001 pgs. 1, 2, and 10. pgs. 1, 2 and 10. pg. 1 and 6. CORPORATE HEADQUARTERS 2975 Stender Way Santa Clara, CA 95054 for SALES: 800-345-7015 or 408-727-6116 fax: 408-492-8674 www.idt.com* for Tech Support: 408-330-1753 email: FIFOhelp@idt.com P Pkg: www.idt.com/docs/PSC4003.pdf J Pkg: www.idt.com/docs/PSC4008.pdf DB Pkg: www.idt.com/docs/PSC4082.pdf
*To search for sales office near you, please click the sales button found on our home page or dial the 800# above and press 2. The IDT logo is a registered trademark of Integrated Device Technology, Inc. and the ST-BUS(R) is a trademark of Mitel Corp.
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