DS2181A
4 of 32
NOTES:
1. These output status pins are only available on the DS2181AQ.
2. If the TEST pin is tied low and CCR.1=0, then these pins will be tri–stated.
RECEIVE PIN DESCRIPTION (40-PIN DIP ONLY) Table 2B
PIN SYMBOL TYPE DESCRIPTION
21 RRA O
Receive Remote Alarm. Transitions high when alarm detected;
returns low when alarm cleared.
22 RMDA O
Receive Distant Multiframe Alarm. Transitions high when alarm
detected; returns low when alarm cleared.
23 RAF O
Receive Alignment Frame. High during frames containing the frame
alignment signal, low otherwise.
24 RCLK I
Receive Clock. 2.048 MHz primary clock.
25 RCHCLK O
Receive Channel Clock. 256 kHz clock, identifies timeslot
boundaries; useful for serial-to-parallel conversion of channel data.
26 RSER O
Receive Channel Clock. 256 kHz clock, identifies timeslot
boundaries; useful for serial-to-parallel conversion of channel data.
27 RFSYNC O
Receive Frame Sync. Trailing edge indicates start of frame.
28 RMSYNC O
Receive Multiframe Sync. Low-high transition indicates start of
CAS multiframe; held high during frame 0.
29 RSD O
Receive Signaling Data. Extracted timeslot 16 data; updated on
rising edge of RCLK.
30 RSTS O
Receive Signaling Timeslot. High during timeslot 16 of every frame,
low otherwise.
31 RCSYNC O
Receive CRC4 Sync. Low-high transition indicates start of CRC4
multiframe; held high during CRC4 frames 0 through 7 and held low
during frames 8 through 15.
33
RST
I
Reset. Must be asserted during device power-up and when changing
to/from the hardware mode.
34
35
RPOS
RNEG
I
Receive Bipolar Data. Sampled on falling edges of RCLK. Tie
together to receive NRZ data and disable BPV monitor circuitry.
36 RCL O
Receive Carrier Loss. Low-high transition indicates loss of carrier.
37 RBV O
Receive Bipolar Violation. Pulses high during detected bipolar
violations.
38 RFER O
Receive Frame Error. Pulses high when frame alignment, CAS
multiframe alignment or CRC4 words received in error.
39 RLOS O
Receive Loss of Sync. Indicates synchronizer status; high when
frame, CAS and/or CRC4 multiframe search underway, low
otherwise.
