
DS21Q55 Quad T1/E1/J1 Transceiver
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Software or hardware based
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Interrupt generated on change of signaling data
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Receive signaling freeze on loss-of-sync,
carrier loss, or frame slip
§ Addition of hardware pins to indicate carrier loss
and signaling freeze
§ Automatic RAI generation to ETS 300 011
specifications
§ Access to Sa and Si bits
§ Option to extend carrier loss criteria to a 1ms
period as per ETS 300 233
§ Japanese J1 support
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Ability to calculate and check CRC6 according
to the Japanese standard
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Ability to generate Yellow Alarm according to
the Japanese standard
TDM Bus
§ Dual two-frame independent receive and transmit
elastic stores
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Independent control and clocking
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Controlled slip capability with status
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Minimum delay mode supported
§ 16.384MHz maximum backplane burst rate
§ Supports T1 to CEPT (E1) conversion
§ Programmable output clocks for fractional T1, E1,
H0, and H12 applications
§ Interleaving PCM bus operation
§ Hardware signaling capability
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Receive signaling reinsertion to a backplane
multiframe sync
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Availability of signaling in a separate PCM
data stream
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Signaling freezing
§ Ability to pass the T1 F-bit position through the
elastic stores in the 2.048MHz backplane mode
§ Access to the data streams in between the
framer/formatter and the elastic stores
§ User-selectable synthesized clock output
HDLC Controllers
§ Two independent HDLC controllers per port
§ Fast load and unload features for FIFOs
§ SS7 support for FISU transmit and receive
§ Independent 128-byte Rx and Tx buffers with
interrupt support
§ Access FDL, Sa, or single/multiple DS0 channels
§ DS0 access includes Nx64 or Nx56
§ Compatible with polled or interrupt driven
environments
§ Bit-oriented code (BOC) support
Test and Diagnostics
§ Programmable on-chip bit error-rate testing
§ Pseudorandom patterns including QRSS
§ User-defined repetitive patterns
§ Daly pattern
§ Error insertion single and continuous
§ Total bit and errored bit counts
§ Payload error insertion
§ Error insertion in the payload portion of the T1
frame in the transmit path
§ Errors can be inserted over the entire frame or
selected channels
§ Insertion options include continuous and absolute
number with selectable insertion rates
§ F-bit corruption for line testing
§ Loopbacks: remote, local, analog, and per-channel
loopback
Extended System Information Bus
§ Host can read interrupt and alarm status on up to 8
ports with a single bus read
User-Programmable Output Pins
§ Four user-defined output pins for controlling
external logic
Control Port
§ 8-bit parallel control port
§ Multiplexed or nonmultiplexed buses
§ Intel or Motorola formats
§ Supports polled or interrupt environments
§ Software access to device ID and silicon revision
§ Software reset supported
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Automatic clear on power-up
§ Hardware reset pin