DS21Q42T View Datasheet(PDF) - Dallas Semiconductor -> Maxim Integrated

Part Name

Description

MFG CO.

DS21Q42T

Enhanced QUAD T1 FRAMER

Dallas Semiconductor -> Maxim Integrated 

3. DS21Q42 PIN FUNCTION DESCRIPTION

DS21Q42

TRANSMIT SIDE PINS

Signal Name: TCLK

Signal Description: Transmit Clock

Signal Type: Input

A 1.544 MHz primary clock. Used to clock data through the transmit side formatter.

Signal Name: TSER

Signal Description: Transmit Serial Data

Signal Type: Input

Transmit NRZ serial data. Sampled on the falling edge of TCLK when the transmit side elastic store is

disabled. Sampled on the falling edge of TSYSCLK when the transmit side elastic store is enabled.

Signal Name: TCHCLK

Signal Description: Transmit Channel Clock

Signal Type: Output

A 192 KHz clock which pulses high during the LSB of each channel. Synchronous with TCLK when the

transmit side elastic store is disabled. Synchronous with TSYSCLK when the transmit side elastic store is

enabled. Useful for parallel to serial conversion of channel data. This function is available when FMS = 1

(DS21Q41 emulation).

Signal Name: TCHBLK

Signal Description: Transmit Channel Block

Signal Type: Output

A user programmable output that can be forced high or low during any of the 24 T1 channels.

Synchronous with TCLK when the transmit side elastic store is disabled. Synchronous with TSYSCLK

when the transmit side elastic store is enabled. Useful for blocking clocks to a serial UART or LAPD

controller in applications where not all T1 channels are used such as Fractional T1, 384 Kbps service, 768

Kbps or ISDN–PRI . Also useful for locating individual channels in drop–and–insert applications, for

external per–channel loopback, and for per–channel conditioning. See Section 12 for details.

Signal Name: TSYSCLK

Signal Description: Transmit System Clock

Signal Type: Input

1.544 MHz or 2.048 MHz clock. Only used when the transmit side elastic store function is enabled.

Should be tied low in applications that do not use the transmit side elastic store. Can be burst at rates up

to 8.192 MHz.

Signal Name: TLCLK

Signal Description: Transmit Link Clock

Signal Type: Output

4 KHz or 2 KHz (ZBTSI) demand clock for the TLINK input. See Section 15 for details.

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