DS2148T Maxim Integrated Products, DS2148T Datasheet - Page 43

• Manufacturer Part Number: DS2148T
• Description: IC LIU E1/T1/J1 5V 44-TQFP
• Manufacturer: Maxim Integrated Products
• Type: Line Interface Units (LIUs)r

Specifications of DS2148T

• Number Of Drivers/receivers: 1/1
• Protocol: T1/E1/J1
• Voltage - Supply: 4.75 V ~ 5.25 V
• Mounting Type: Surface Mount
• Package / Case: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

RDNCD2 (10H): RECEIVE DOWN CODE DEFINITION REGISTER 2
6.2 Loopbacks
6.2.1 Remote Loopback (RLB)
the clock/data recovery state machine will be looped back to the transmit path passing through the jitter
attenuator if it is enabled. The data at the RPOS and RNEG pins will be valid while data presented at
TPOS and TNEG will be ignored
If the Automatic Remote Loopback Enable (CCR6.5) is set to a one, the DS2148 will automatically go
into remote loopback when it detects the loop up code programmed in the Receive Up Code Definition
Registers (RUPCD1 and RUPCD2) for a minimum of 5 seconds. When the DS2148 detects the loop
down code programmed in the Receive Loop Down Code Definition registers (RDNCD1 and RDNCD2)
for a minimum of 5 seconds, the DS2148 will come out of remote loopback. Setting ARLBE to a zero
also can disable the ARLB.
6.2.2 Local Loopback (LLB)
When LLB (CCR6.7) is set to a one, the DS2148 is placed into local loopback. In this loopback, data on
the transmit-side will continue to be transmitted as normal. TCLK and TPOS/TNEG will pass through the
jitter attenuator (if enabled) and be output at RCLK and RPOS/RNEG. Incoming data from the line at
RTIP and RRING will be ignored. If Transmit Unframed All Ones (CCR3.7) is set to a one while in LLB,
TTIP and TRING will transmit all ones while TCLK and TPOS/TNEG will be looped back to RCLK and
RPOS/RNEG
When RLB (CCR6.6) is enabled, the DS2148 is placed into remote loopback. In this loopback, data from
(MSB)
C15
SYMBOL
C15
C14
C13
C12
C11
C10
C9
C8
(Figure
C14
1-1).
POSITION
RDNCD2.7
RDNCD2.6
RDNCD2.5
RDNCD2.4
RDNCD2.3
RDNCD2.2
RDNCD2.1
RDNCD2.0
C13
(Figure
DESCRIPTION
Receive Down Code Definition Bit 15
Receive Down Code Definition Bit 14
Receive Down Code Definition Bit 13
Receive Down Code Definition Bit 12
Receive Down Code Definition Bit 11
Receive Down Code Definition Bit 10
Receive Down Code Definition Bit 9
Receive Down Code Definition Bit 8
1-1).
C12
43 of 73
C11
C10
C9
(LSB)
C8