48DS3/EC1/TransMUX (LNW20)

Electrical specification

DS3 interfaces transmit/receive a standard electrical DS3 signal as specified in GR-499-CORE, Section 9 (44.736 Mb/s rate, DSX-3 interconnect specification, bipolar 3-zero substitution (B3ZS) encoding).

The LNW20 provides 48 ports supporting DS3, EC1, and TMUX functionality on a port-by-port basis. Each port can be individually provisioned as DS3 or EC1 (unchannelized), or as TransMUX (channelized DS3s). With the LNW20, one high-density pack can be used for all DS3, EC1, and/or TransMUX applications.

LNW20 can be 1x1 protected or function in 0x1 unprotected mode. It supports hairpins to other packs in the shelf, and between ports on the same pack.

LNW20 can always occupy slots A1/A2 through D1/D2. Only certain Main packs can support the LNW20 in G1/G2 slots. Because the G1/G2 slots do not have any electrical backplane connections, only optical or "port-less TMUX" can work in the G slots. The following Mains support the LNW20 in G1/G2 slots and portless operation in all slots:

• OC-48: LNW27, LNW29, LNW32, LNW76, LNW82, LNW202

• OC-192: LNW56, LNW58, LNW59, LNW502, LNW504

• Switch pack: LNW80

Ported channelized DS3 mode of operation

The LNW20 TransMUX card that can collect various DS1 signals from around a ring and combine them into a channelized DS3 signal.

Transmit functions

• Receives a B3ZS-encoded DS3 signal from a DSX-3

• Recovers DS3 clock and NRZ data

• Calculates parity errors on the DS3 input

• Demultiplexes the M13 or C-bit formatted DS3 signal into 28 DS1s

• Maps the 28 DS1s into VT1.5s and then into an STS-1

• Inserts STS-1 path overhead

• Provides the STS-1 signal to the OLIU circuit packs

Receive functions

• Interprets the STS-1 pointer values

• Terminates the STS-1 path

• Disinterleaves the STS-1 signal into 28 VT1.5s and interprets VT pointer values

• Converts the VT1.5 signals to 28 DS1 signals

• Multiplexes the 28 DS1 signals to an M13 or C-bit formatted DS3 signal

• B3ZS encodes the outgoing DS3 signal

• Pre-equalizes the DS3 signal (with LBO) and transmits it to a DSX-3

Unchannelized DS3 operation

The low-speed DS3 interfaces transmit/receive a standard electrical DS3 signal as specified in GR-499-CORE, Section 9 (44.736 Mb/s rate, DSX-3 interconnect specification, bipolar 3-zero substitution (B3ZS) encoding). However, the signal does not have to contain a standard DS3 frame.

EC-1 operation

The EC-1 low-speed interfaces provide transport of any STS-1 signal compatible with the electrical STS-1 interface specification in GR-253-CORE, Issue 3. The low-speed EC-1 port can be provisioned to provide STS-1 path termination functions for a VT1.5 structured STS-1 with an asynchronous DS1 mapping.

The low-speed EC-1 interfaces transmit/receive a standard electrical EC-1 signal as specified in GR-253-CORE, Issue 3 (51.844 Mb/s rate, STSX-1 interconnect specification, bipolar 3-zero substitution (B3ZS) encoded and scrambled).

Line build-outs (LBOs)

Line build-outs are software-provisionable. The maximum distance depends on the cable type.

Table 10-3: DS3/EC-1 cable lengths

Cable type	LBO in	LBO out
728A/B	0–225 ft.	225–450 ft.
735A	0–112 ft.	112–225 ft.

DS3 portless mode of operation

The LNW20 can also function in portless mode. Portless mode does not utilize any of the electrical ports on the pack. When operating in portless mode, LNW20 converts channelized DS3 signals that enter Alcatel-Lucent 1665 DMX on a SONET STS-1 interface (on another pack) to VT mapped STS-1s. This VT-mapped STS-1 is cross-connected at the VT level in the Main packs (at least one side of the cross-connect is OCn/EC1) to any interface that supports the signal structure today (DS1, channelized DS3, EC1, optical). Portless mode can be provisioned on a per-port basis when VLF Mains are used. When non-VLF Mains are used, odd numbered ports can be configured as portless and the corresponding even-numbered port will be unavailable for service.