XRT83SL38IB datasheet(39/88 Pages) EXAR

39 / 88 page

XRT83SL38

REV. 1.0.2

OCTAL T1/E1/J1 SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR

RECEIVE 1:1 & 1+1 REDUNDANCY

For 1:1 and 1+1 redundancy, the receivers on the primary card should be programmed for Internal Impedance

mode. The receivers on the backup card should be programmed for External Impedance mode. Since there is

no external resistor in the circuit, the receivers on the backup card will be high impedance. This key design

feature eliminates the need for relays and provides one bill of materials for all interface modes of operation.

Select the impedance for the desired mode of operation, T1/E1/J1. To swap the primary card, set the backup

card to Internal Impedance mode, then the primary card to External Impedance mode. See Figure 14 for a

simplified block diagram of the receive section for a 1:1 and 1+1 redundancy scheme.

NOTE: For simplification, the over voltage protection circuitry was omitted.

N+1 REDUNDANCY

FIGURE 13. SIMPLIFIED BLOCK DIAGRAM OF THE TRANSMIT SECTION FOR 1:1 & 1+1 REDUNDANCY

FIGURE 14. SIMPLIFIED BLOCK DIAGRAM - RECEIVE SECTION FOR 1:1 AND 1+1 REDUNDANCY

T1/E1 Line

Backplane Interface

Primary Card

Backup Card

XRT83SL38

Line Interface Ca rd

0.68

μ F

0.68

μ F

TxTS EL=1, Internal

1:2 or 1:2.45

RxT SEL=0, External

RxT SE L=1, Internal

Backplane Interface

Primary Card

B ackup Card

XRT 83SL38

Line Interface Card

T1/E1 Line

1:1

XRT83SL38IB 데이터시트(PDF) 39 Page - Exar Corporation