User guide

77
the supervision circuit card includes a hard-wired sequencer that exchanges
channel supervi- sory messages with the network and parity-detection cir-
cuits that check incoming speech signals; the circuits are shared by all 120
speech channels. The circuit card also includes a processor bus interface
with interrupt capabilities.
NT2X35 — This DCM interface (DS1 line) circuit card contains the DS1
transmit and receive interface circuits. The circuit card sends alarm, error,
and administration data to the signaling circuit card over the maintenance
bus. It also includes a number of maintenance features such as local alarm
input, remote alarm, slips, bipolar violation outputs, slip buffer phase mon-
itoring outputs for office synchronization, and card-present output. The
DCM interface also incorporates looparound for the DS1 circuits.
NT2X36 — The network interface (NI) card is located in the LM or the
DCM. Up to four speech links (0 - 3) from the network (receive) enter the
LM at the Network Interface card. In this card, signals on the speech links
are converted from diphase serial format to unipolar serial data, and the
clock and frame pulses are extracted. The DCM NI card contains eight
biphase modulators, one for both planes of the four DS30 ports. The circuit
card includes parity generation for signals sent to the network as well as
maintenance looparound circuits for the eight speech bits.
NT2X37 — This tone circuit card in the DCM contains a digital tone gen-
erator and a channel memory, controls tone insertion and looparound. The
tone circuit card generates dial tone, alternative dial tone, audible ring, and
multifrequency (MF) signaling signals.
NT2X38 — This DCM signalling card contains circuits that extract the
A/B signaling bits from the DS1 data streams received from the DCM
interface (DS1 line) circuit cards. A filter eliminates the effects of contact
bounce and carrier hits, and a ROM-controlled scanner monitors buffers
and reports changes in received A/B bits. Buffers and timers are used to
produce output pulses and to insert A/B bits onto the speech bus, and pro-
vides line-monitoring and maintenance circuits for all DCM IF (DS1 line)
circuit cards.
NT2X45 — The trunk module (TM) interface card is used in the TM,
MTM, DRAM, and OAU shelves. The TM interface card serves as the net-
work interface for both planes of the network. In addition to providing two
2-way interfaces for the two transmission paths from both network planes,
it contains message registers, bit and channel timing circuits, parity-check-
ing circuits, and circuits
that reformat data.
NT2X48
— A digital 4-channel dual-tone multifrequency (DTMF) or dig-
itone (DGT) receiver. NT2X48AA = DTMF; NT2X48AB = DGT;
NT2X48BB = ESA DGT; NT2X48CA = A-law DTMF receiver (interna-
tional—Turkey); NT2X48CB
=
DTMF for British Telecom; NT2X48CC
A-law DTMF for U.K.
NT2X53 — The trunk module (TM) control card is used in the TM MTM,
DRAM, and OAU shelves. This card includes message registers as well as
bit and channel timing, parity-checking, and data-reformatting circuit.
This circuit includes three controllers that handle trunk, network, and integ-
rity messages, and it generates enabling signals for the 30 individual trunk
interfaces.
NT2X59 — The A-law TM CODEC with BT tones card is used in the TM,
MTM, RMM, DRAM, and OAU shelves. The card codes pulse amplitude
modulation (PAM) signals into PCM and decodes PCM signals into PAM
signals. The card also produces PCM tones for signaling and supervision
purposes. The NT2X59EA is the DMS-250 CODEC.
NT2X70
— A dc-to-dc regulated power converter card. It works from a
-48V dc input and supplies voltages of +5V, -5V, +12V, and -12V, each
with a common ground. Some features include fixed current limiting,
over-voltage/under-voltage shutdown, an interlock (to ensure that 5V is
present before +12V) and dc isolation between input and output. An
on-off-reset switch (Converter Fail) LED is provided to operate in conjunc-
tion with a frame supervisory panel (FSP) power control and alarm circuit.
CAUTION:
When replacing a NT2X70AF Power Converter, follow the
replacement procedures within the NTP.
NT2X90 — An incoming/outgoing (IC/OG) test trunk card that provides
and interface between a TM, MTM, ISM, or RMM and test facilities such
as the #14LTD, #3LTD, CALRS, and MLT. It provides access to sub-
scriber lines through the metallic test access (MTA) network and is also
used for incoming operator verification. The NT2X90AD version includes
all the “AC” version capabilities in addition to “on-hook dc signature,”
“bypass initiate signal detector,” and “ring ground signal detector” capabil-
ities.
NT3X09 —The Metallic Test Access (MTA) card provides 8 by 8 two wire
metallic matrix for cross connection between the test equipment, test card,
line and line card.
NT3X17 — This incoming crosspoint card, used in the NT0X48 Junctored
Network. The eight outputs from IF-0 and IF-1, each representing 32 chan-
nels of serial data, enter the incoming formatter and are converted to 32
sets of parallel data words, 10-bits per word, having 8 words per set.
NT3X18 — This outgoing crosspoint card, used in the NT0X48 J-Net,
converts incoming parallel speech and signalling data to serial.