MT9074_05 Datasheet, PDF (56/151 Pages) Zarlink Semiconductor Inc – T1/E1/J1 Single Chip Transceiver

MT9074
Data Sheet
Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8
00011110
00001011
00001011
00011110
10011110
10001011
10001011
10011110
Table 18 - Digital Milliwatt Pattern (T1)
Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8
00110100
00100001
00100001
00110100
10110100
10100001
10100001
10110100
Table 19 - A-Law Digital Milliwatt Pattern (E1)
Per Channel Inversion
When bit six (PCI) in the Per Time Slot Control Word is set both transmit and receive data for the selected channel
is inverted before going onto the line / DSTo respectively.
Transmit Message
When bit seven (TXMSG) in the Per Time Slot Control Word is set the data transmit in the selected channel is
sourced from the transmit message word in Master Control page 1.
Alarms
The following alarms are detected by the receiver in T1 mode. Each may generate a maskable interrupt:
• Yellow alarm - in D4 mode there are two possible yellow alarm signals. If control bit D4SECY is set low,
(page 1H, address 11Hb it 1) the criteria for a yellow alarm is an excess of ’0’s (more than 285) in bit position
2 of incoming DS0 channels during an integration period of 1.5 milliseconds. It is cleared after more than 3
’1’s are detected in bit position 2 of normal data in a 1.5 millisecond integration period. If D4SECY is set high
the secondary yellow alarm is selected. The detection criteria becomes 2 consecutive’1’s in the Sbit position
of the 12th frame. In ESF mode the alarm is set if the pattern 0000000011111111 is received in seven or
more codewords out of ten.;
• All Ones - This bit (page 3H, address 11H, bit 3) is set if less than six zeros are received on the incoming line
data during a 3 ms interval
• Loss of Signal - a loss of signal condition occurs when the receive signal level is lower than 40 dB below the
nominal signal level for at least a millisecond or when 192 consecutive zeros have been received. A loss of
signal condition will terminate when than average ones density of at least 12.5% has been received over a
56
Zarlink Semiconductor Inc.