Rainbow Electronics DS2186 - Manual (Page 3)

DS2186
041295 3/11
PIN DESCRIPTION Table 1
PIN SYMBOL TYPE DESCRIPTION
1 TAIS I Transmit Alarm Indication Signal. When high, output data is
forced to all ones at the TCLK (LB=0) or LCLK (LB=1) rate.
2 ZCSEN I Zero Code Suppression Enable. When high, B8ZS or HDB3
encoder enabled.
3 TCLKSEL I Transmit Clock Select. Tie to V
SS
for 1.544 MHz (T1) applica-
tions, to V
DD
for 2.048 MHz (CEPT) applications.
4
5
6 LEN0
LEN1
LEN2 I Length Select 0, 1 and 2. State determines output T1 waveform
shape and characteristics.
7 V
DD
– Positive Supply. 5.0 volts.
8
9 TTIP,
TRING
O Transmit Tip and Ring. Line driver outputs; connect to transmit
line transformer.
10 V
SS
– Signal Ground. 0.0 volts.
11 LF O Line Fault. Open collector active low output. Held low during an
output driver fault and/or failure; tri–stated otherwise.
12
13 MRING,
MTIP
I Monitor Tip and Ring. Normally connected to TTIP and TRING.
Sense inputs for line fault detection circuitry.
14 LB I Loopback. When high, input data is sampled at LPOS and LNEG
on falling edges of LCLK; when low, input data is sampled at TPOS
and TNEG on falling TCLK.
15
16 TNEG,
TPOS
I Transmit Data. Sampled on falling edges of TCLK when LB=0.
17 TCLK I Transmit Clock. 1.544 MHz or 2.048 MHz primary data clock.
18
19 LNEG,
LPOS
I Loopback Data. Sampled on falling edges of LCLK when LB=1.
20 LCLK I Loopback Clock. 1.544 MHz or 2.048 MHz loopback data clock.
INPUT DATA MODES
Input data is sampled on the falling edge of TCLK or
LCLK and can be bipolar (dual rail) or unipolar (single
rail, NRZ). TPOS, TNEG and TCLK are the data and
clock inputs when LB=0, LPOS, LNEG and LCLK when
LB=1. TPOS and TNEG (LPOS and LNEG) must be tied
together in NRZ applications.
ZERO CODE SUPPRESSION MODES
Transmitted data is treated transparently (no zero code
suppression) when ZCSEN=0. HDB3 code words re-
place any all–zero nibble when ZCSEN=1 and
TCLKSEL=1. B8ZS code words replace any incoming
all–zero byte when ZCSEN=1 and TCLKSEL=0.
ALARM INDICATION SIGNAL
When TAIS is set, an all ones code is continuously
transmitted at the TCLK rate (LB=0) or the LCLK rate
(LB=1).
WAVE SHAPING
The device supports T1 short loop (DSX–1; 0 to 655
feet), T1 long loop (CSU; 0 dB, –7.5 dB and –15 dB) and
CEPT (CCITT G.703) pulse template requirements.
On–chip laser trimmed delay lines clocked by either
TCLK or LCLK control a precision digital–to–analog
converter to build the desired waveforms, which are
buffered differentially by the line drivers.