XE2420-ITR Ver la hoja de datos (PDF) - Unspecified

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XE2420-ITR

The World’s First Complete PLCC Packaged Modem

Unspecified 

XE2420 Pin Configuration

Ring 1

Tip 2

N/C 3

N/C 4

N/C 5

N/C 6

N/C 7

N/C 8

N/C 9

/Hint 10

Vui 11

XE2420 and XE2421

22 VCC

21 Reset

20 /TXD

19 /RXD

(top)

18 /RTS

17 /CTS

16 /DSR

15 /DCD

14 /DTR

13 /RI

12 Gnd

Pin Descriptions

PIN NAME DESCRIPTION

1 Ring

3

Tip

4-9

10 /Hint

11 Vui

12 Ground

Along with the Tip signal, Ring provides the connection to the telephone line. FCC Part 68

Rules require a 1500 volt isolation barrier between the telephone line and all other circuits.

This isolation must be preserved throughout the system.

The telephone company places a DC “Battery” voltage across Tip and Ring on all public switched

telephone lines. The XEV90C will operate regardless of the polarity of this “Battery” voltage.

The “Battery” voltage drives up to 100 milliamps of DC loop current.

UL1950 requires minimum creepage and clearances distances be maintained between the Tip

and Ring traces and all other circuits. Clearance is the shortest distance between conductive

circuits; creepage is the distance between conductive surfaces along the surface.

Along with the Ring signal, Tip provides the connection to the telephone line. FCC Part 68

Rules require a 1500 volt isolation barrier between the telephone line and all other circuits.

This isolation must be preserved throughout the system.

No Connection

/Hint, Handset Interrupt, is an active low output from the XE2421. This pin is not used on the

XE2420. On the XE2421 /Hint indicates that another device as attempted to sieze the attached

line. Handset Interrupt is activated for approximately one second if another device siezes the

telephone line while the XE2421 is on-line. When Handset Interrupt is activated, the XE2421

initiates an automatic disconnect from the telephone line.

Vui provides uninterrupted power to the XE2420 ring detect circuit. Placing 5 volt power on

Vui insures that the CD/RI ouput will operate when VCC is removed from the modem.

Ground provides the reference voltage for all host interface signals.

XECOM

(3)

XE2420

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