txc-03456 TranSwitch Corporation, txc-03456 Datasheet - Page 72

• Manufacturer Part Number: txc-03456
• Description: Device Level Mapper
• Manufacturer: TranSwitch Corporation

Address
13
14
Bit
5
4
3
2
1
0
7
6
POHRAM
TCAISEN
EAISEN
Symbol
TUNEQ
SLBK
LLBK
COR
LHZ
Transmit Unequipped Status: This bit works in conjunction with control
bit POHEUQ for generating an unequipped channel. The Path Overhead
Byte enable feature must be enabled (POHDIS lead is high).
TUNEQ POHEUQ
Path Overhead Bytes to RAM: A 1 enables the transmit POH bytes
(e.g. EXH4 is equal to 1) from the external POH interface to be written
into RAM prior to transmission. A 0 still enables selected external inter-
face POH bytes to be transmitted, but the RAM locations are not written
with the value of the external POH byte. Instead, the RAM locations will
hold the microprocessor-written values.
Force Receive Line to High Impedance: A 1 forces the receive byte or
nibble data (RXDn), and line output clock (RXCO) to a high impedance
state, until this bit is written with a 0. This bit is set to 1 after a device
reset.
Line Loopback: A 1 written into this location enables the received line
signal to be looped back as the transmit line signal. The received data
and clock are provided at either the byte or nibble receive line interfaces.
SDH/SONET Loopback: A 1 written into this location enables a VC-4/
SPE loopback. This feature is not valid when the PTEN pin is set to 1.
Non-Saturating Performance Counters Enable: A 1 enables the per-
formance counters to be non-saturating with roll over capability. A 0
causes all performance counters to be saturating, stopping at their max-
imum value, with clear on read capability.
External Loss Of Signal AIS Enable: A 1 enables a 140 Mbit/s AIS to
be transmitted when a low is applied to EXLOS (pin 85). A 0 disables an
external loss of signal indication from transmitting an AIS.
Transmit Loss of Clock AIS Enable: A 1 enables the L4M to send a
140 Mbit/s AIS when a transmit loss of clock alarm (TLOC) is detected.
A 0 disables a transmit loss of clock alarm (TLOC) from transmitting an
AIS.
0
1
1
X
0
1
DATA SHEET
- 72 -
Normal Operation
Unequipped Channel. POH and payload bytes are
transmitted as 0.
Supervisory Unequipped Channel. POH bytes
enabled. Payload bytes transmitted as 0.
Action
Description
Ed. 1A, January 2000
TXC-03456
TXC-03456-MB
L4M