7

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SP505_00_08308

Pin 7 — SCTEN — Enables SCT receiver;

active high; TTL input.

Pin 8 — LATCH — Latch control for decoder

bits (pins 9-2), active low. Logic high input

will make decoder transparent.

Pins2–9—DEC

receiver decode register; configures trans-

mitter and receiver modes; TTL inputs.

Pin 8 — RLEN — Enables RL driver; active

low; TTL input.

Pin 23 — STEN — Enables ST driver; active

low; TTL input.

POWER SUPPLIES

Pins 25, 33, 4, 48, 55, 62, 73, 74 — V

CC

— +5V input.

Pins 29, 34, 43, 46, 50, 53, 57, 60, 64, 72,

75 — GND — Ground.

Pin 27 — V

— Connects from V

capacitor size is 22µF, 6V.

Pin 32 — V

— Connects from ground to V

capacitor size is 22µF, 6V.

Pins 26 and 30 — C



+

and C



–

— Charge

PumpCapacitor —ConnectsfromC



+

toC



–

.

Suggested capacitor size is 22µF, 6V.

Pins 28 and 3 — C

2

+

and C

2

–

— Charge

PumpCapacitor —ConnectsfromC

2

+

toC

2

–

.

Suggested capacitor size is 22µF, 6V.

Pin45—RL(b)—RemoteLoopback;analog

output, non-inverted; sourced from RL.

Pin47—RL(a) —RemoteLoopback;analog

output inverted; sourced from RL.

Pin 49— LL(b) — Local Loopback; analog

output, non-inverted; sourced from LL.

Pin 5 — LL(a) — Local Loopback; analog

output, inverted; sourced from LL.

Pin 52 — RS(b) — Ready To Send; analog

output, non-inverted; sourced from RTS.

Pin 54 — RS(a) — Ready To Send; analog

output, inverted; sourced from RTS.

Pin 56 — TR(b) — Terminal Ready; analog

output, non-inverted; sourced from DTR.

Pin 58 — TR(a) — Terminal Ready; analog

output, inverted; sourced from DTR.

Pin 66 — CS(a)— Clear To Send; analog

input, inverted; source for CTS.

Pin 67 — CS(b)— Clear To Send; analog

input, non-inverted; source for CTS.

Pin 68 — DM(a)— Data Mode; analog input,

inverted; source for DSR.

Pin 69 — DM(b)— Data Mode; analog input,

non-inverted; source for DSR

Pin78—DSR—DataSetReady;TTLoutput;

sourced from DM(a), DM(b) inputs.

Pin 80 — CTS— Clear To Send; TTLoutput;

sourced from CS(a) and CS(b) inputs.

CONTROL REGISTERS

Pins 2 — SDEN — Enables TxD driver,

active low; TTL input.

Pins 3 — TREN — Enables DTR driver,

active low; TTL input.

Pins 4 — RSEN — Enables RTS driver,

active low; TTL input.

Pins 5 — LLEN — Enables LL driver, active

low; TTL input.

Pin 6 — TTEN — Enables TT driver, active

low; TTL input.