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Table of Contents
i
Chapter 1. Introduction …………………………………………... 1
1.1 General …………………………………………………….. 1
1.2 Functional Description ……………………………………. 1
1.3 Technical Specifications …………………………………... 3
1.4 T1 Signal Structure ……………………………………….. 4
1.5 Applications / Capabilities ………………………………… 6
Chapter 2. Installation ……………………………………………. 9
2.1 General …………………………………………………….. 9
2.2 Site Preparation …………………………………………… 9
2.3 Mechanical Assembly ……………………………………... 9
2.4 Electrical Installation ……………………………………… 10
2.5 Power Supply Modules …………………………………… 12
Chapter 3. Data Modules ………………………………………… 13
3.1 Data Modules Overview …………………………………... 13
3.2 Data Module LED Indicators …………………………….. 16
3.3 V.35 Data Module …………………………………………. 17
3.4 RS-530 Data Module ……………………………………… 18
3.5 RS-449 Data Module ……………………………………… 19
3.6 X.21 Data Module …………………………………………. 20
3.7 ET10 Ethernet Module ……………………………………. 21
Table of Contents
ii
Chapter 4. Loop Back Testing …………………………………... 23
4.1 General ……………………………………………………... 23
4.2 User Activate Loop Back …………………………………. 23
4.3 T1 Link local digital loop back ……..…………….………. 23
4.4 Data Port local analog loop back ……………….………… 24
4.5 T1 Link remote loop back ………………………………… 24
4.6 BERT local loop back ……………...……………………… 25
4.7 BERT remote loop back for system test .………………… 25
Chapter 5. Troubleshooting ……………………………………… 27
5.1 General …………………………………………………….. 27
5.2 Connections .……………………………………………….. 27
5.3 Configuration ..…………………………………………….. 28
5.4 FT1 Card testing .………………………………………….. 29
Appendix A. DIP Switch Setting Tables ………………………. 33
Notes: …………………………………………………………………. 39
Technical Inquiry Card
Chapter 1. Introduction
1 TRM-01 APR 2000
1.1 General
The TRM-01 is a 4U (7") high 19" Rack, containing multiple T1
CSU/DSUs for Fractional T1 network access. The TRM-01 provides an
economic solution in high density T1 installations such as central offices. There
are 13 slots available for installation of FT1 Cards (G.703 Fractional T1) into
the TRM-01 compact RACK. An optional SNMP Card may be installed into
the last slot, for local and remote management purposes, leaving 12 slots
available for FT1 Cards. Each FT1 Card may be linked to a remote TTU-01
or TTU-01A stand alone T1 CSU/DSU Access Unit to provide a variety of
LAN-to-LAN, Video Conference, Host to client, or Host to Host applications
over T1 Network Services.
1.2 Functional Description
The TRM-01 may optionally incorporate two separate Power Module
supplies, which, depending on the model, may derive power from either an AC
power source (95~250VAC) or DC (-54 to -42VDC) power source. The power
supply modules provide for power redundancy and are hot swappable even
during the FT1 Cards' transmissions. The TRM-01 provides all interface
connections on the rear panel. BNC and Terminal Blocks are used for T1 Line
interface connections, while optional cable adapters are used to convert the
HDB26 DCE ports to V.35, RS-530, RS-449 or X.21. When an FT1/ET10
Card (Ethernet bridge interface) is installed in the TRM-01, the card can
provide either Ethernet bridging or repeating (non-filter mode) over the T1 link.
When cards are inserted in slots, LEDs on the front panel will show both the T1
Line and Data port statuses, Power Status, and any Alarm indications.
The FT1 Card data channels support user-selectable transmission rates,
which are integer multiples of 56Kbps or 64Kbps (fractional T1), up to a
maximum 2048Kbps (unframed T1), for a line attenuation of up to 43 dB on
twisted pair or coax cables. This provides an approximate operating range of up
to 2Km (over 22AWG wire).
The FT1 Card packs its data channel into user selected T1 link time slots.
The unused time slots may have IDLE code of 0xff or 0x7e inserted (in frame
mode) or they may insert the receive side time slot's data (In cascade mode).
The TRM-01 has three major types of FT1 Card data port interface
modules, which provide the desired interface: V.35, RS-530, or ET10 Ethernet.
X.21 and RS-449 interfaces are fully supported using the RS-530 (public) card
and appropriate X.21 and RS-449 adapter cables.
Chapter 1. Introduction
2 TRM-01 APR 2000
The TRM-01 and FT1 Cards fully meet all T1 specifications including
ITU-T G.703, G.704, G.706, G.732, and G.823.
Each FT1 Card features V.54 diagnostic capabilities for performing local
loop back and remote loop back. The operator at either end of the T1 line may
test both the FT1 Card and the line in the digital loop back mode. The loop
back is controlled by either a manual push-button switch or by the DTE
interface for V.35 or RS-530.
When the local loop back switch is activated, an internal 511 bit pseudo
random test pattern is generated, according to ITU-T, for direct end-to-end
integrity testing. The Err indicator LED flashes for each bit error detected.
Multiple clock source selection provides maximum flexibility in
connecting both the T1 and user data interface. The T1 link may be clocked
from the recovered receive clock, from user data port, or from an on-card
oscillator.
When the TRM-01 is ordered with an optional SNMP Card, the card is
placed in slot number 13. Each FT1 Card will have DIP Sw7-6 turned ON to
enable remote setting. In this mode, the other DIP switch settings are ignored
while the SNMP Card controls all settings (with the exception of termination
impedance). Control is accomplished either via local control on the
asynchronous RS-232 port with an ASCII terminal or via Ethernet and any
standard SNMP network management software. If the SNMP Card option is
not installed, slot number 13 may hold an additional FT1 Card.
Figure 1-1 : TRM-01 Block Diagram
Chapter 1. Introduction
3 TRM-01 APR 2000
1.3 Technical Specifications
T1 Link User Data Channels
• Framing
Unframed/Framed V.35
D4(SF) RS-530
ESF RS-449
X.21
• Bit Rate
1.544Mbps
• Interface Type
Ethernet 10Base-T
AMI
• I/F Connectors
HDB26 female
• Line Code
B8ZS
100 Ω
• Line Code
NRZ (except
Ethernet)
• Line
Impedance
Balanced
• Receive Level
0 to –36dB
Transmit Level
• Data Rate
1536Kbps(unframe)
nx56 or nx64Kbps
where N equal
1 ~24
Clock Modes Pulse
amplitude
3.00V ±10% (100Ω)
Mode 0
(DCT1)
Rx and Tx clock
recovered from T1
Zero
amplitude
±0.1V
• Transmit Frequency Tracking
Mode 1
(DCE2)
Rx and Tx clock
internal oscillator
Internal
timing
±30ppm
Mode 2
(DTT1)
Sync to Rx clock
(transparent)
Loopback
timing
±50ppm
Mode 3
(DTE2)
Tx from ETC and
Rx from ERC
External
timing
±100ppm
Mode 4
(DTE3)
Tx and Rx both
from ETC
• Jitter
performance
According to ITU-T
G.824
CTS constantly ON
• Complies with
ITU-T G.703,G.704,
G.706,G.733,G824
and ANSI T1 403
DSR constantly ON
except during test
BNC for unbalanced
• I/F connectors
5 pin Molex ™ for
balanced
• Handshaking
control signals
DCD constantly ON
(except during
signal loss)
• Timeslot
Allocation
User Defined
Table 1-1 : TRM-01 Specifications
Chapter 1. Introduction
4 TRM-01 APR 2000
1.4 T1 Signal Structure
The T1 line operates at a nominal rate of 1.544Mbps. The data transferred
over the T1 line is organized into frames, with each T1 frame containing 256
bits. The 256 bits are a total of the 24 time slots, each containing eight bits, that
carry the data payload.
T1 transmission utilizes two main types of framing: Superframe Format
(SF) and Extended Superframe Format (ESF). A T1 framing format that uses
the framing bit to provide maintenance and diagnostic functions. D4-frame - A
T1 line uses the D4 format, also known as the superframe (SF) format, to frame
data at the physical layer. The D4 format consists of 12 consecutive frames,
each separated by framing bits. Framing is necessary in order for equipment
receiving the T1 signal to be able to identify and extract the individual channels.
Superframe Format (SF)
SF - Also known as D4, T1 lines use this format to frame data at the
physical layer. The SF format consists of 12 consecutive frames, each separated
by framing bits.
Extended Superframe Format (ESF)
ESF is a framing format that consists of 24 consecutive frames separated
by framing bits. The ISDN specification advises that you use ESF with ISDN
D-channel signaling.
T1 line signal
The basic T1 line signal is coded using either the Alternate Mark
Inversion (AMI) or B8SZ rule.
Chapter 1. Introduction
5 TRM-01 APR 2000
In the AMI format, “ones” are alternately transmitted as positive and
negative pulses, whereas “zeros” are transmitted as a zero voltage level. AMI is
not used in most 1.544Mbps transmissions because synchronization loss occurs
during long strings of data zeros.
B8ZS: Abbreviation for bipolar with eight-zero substitution . A T-carrier
line code in which bipolar violations are deliberately inserted if user data
contains a string of 8 or more consecutive zeros. Note 1: B8ZS is used to ensure
a sufficient number of transitions to maintain system synchronization when the
user data stream contains an insufficient number of "ones" to do so. Note 2:
B8ZS is used in the European hierarchy at the T1 rate.
T1 link line coding
The TRM-01 supports two T1 line codes:
AMI coding.
B8ZS coding.
T1 framing formats
The TRM-01 supports three frame formats:
Unframed format.
SF Superframe Format.
ESF Extended Superframe Format.
Chapter 1. Introduction
6 TRM-01 APR 2000
1.5 Applications / Capabilities
In the following example, the TRM-01 is installed at an ISP's central
office and provides "last mile" access to corporate customers over dedicated T1
transmission lines. The customer site utilizes a single data port CSU/DSU,
which could be one of our pack series or standalone units. While utilizing
fraction T1 connections, the ISP can provide a variety of bandwidth options to
its customers. By varying timeslot assignments, data rates from 64Kbps up to
1536Kbps may be utilized in frame mode.
The FT1 Cards in the TRM-01 could all be set to internal oscillator
timing or they could receive timing from the DTE on the data port. The remote
units would all be set to recovery.
Figure 1-2 : T1 nest for ISP
In the next application example, the TRM-01 is used in a point-to-point
T1 line environment. Each FT1 Card acts as a stand alone Digital Access Unit,
connecting individual T1 lines to data port interfaces or bridging Ethernet LANs.
For any T1 link, one CSU/DSU should provide internal timing while the linked
unit should be set to recovery.
Figure 1-3 : Point-to-point Application of TRM-01
Chapter 1. Introduction
7 TRM-01 APR 2000
The next example utilizes the cascade capability of the FT1 Cards. In this
example, multiple FT1 Cards are set to “cascade”. Each card is assigned non-
overlapping timeslots of a single T1 line. In cascade mode, the FT1 Card
passes unused timeslot data transparently from Rx to Tx, creating a multiplexer
effect. By careful assignment of timeslots in the T1 frame, the TRM-01 could
be used as a 13 data channel multiplexer. It should also be noted however, that
removal or failure of any one card in this configuration would negatively effect
all other card data throughput.
Figure 1-4 : Multiplexer function (cascade mode) over T1 services
In the last application example, the TRM-01’s FT1 Cards provide
multiple data port connections via T1 lines connected through an T3 multiplexer
from an T3 line. Since the timing is normally passed from the network side, the
FT1 Cards should all be set to recovery.
Figure 1-5 : Multiple T1 Access via E3 multiplexer
Chapter 1. Introduction
8 TRM-01 APR 2000
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Chapter 2. Installation
9 TRM-01 APR 2000
2.1 General
This chapter explains in detail the requirements and procedures for the
installation of the TRM-01 Rack Mount Series T1 Digital Access Unit.
2.2 Site Preparation
Install the TRM-01 within reach of an easily accessible grounded AC
outlet. The outlet should be capable of furnishing 90 to 250 VAC. Allow at least
10cm (4 inch) clearance at the rear of the TRM-01 for signal lines and interface
cables.
2.3 Mechanical Assembly
The TRM-01 is designed for rack mount installation and only requires 4U
space (7") in a standard EIA 19 inch rack. It is highly recommended that the
unit be placed in a rack. The TRM-01 is delivered completely assembled. No
provision is made for bolting the TRM-01 to a tabletop.
Figure 2-1 : Rackmount Installation of the TRM-01 Unit
Chapter 2. Installation
10 TRM-01 APR 2000
2.4 Electrical Installation
2-4-1. Power connection
In the AC model, AC power is supplied to the TRM-01 through a standard
IEC 3-prong receptacle, located on the rear of the chassis. In the DC model,
DC –48V is connected to the lower terminal block, observing the proper
polarity. The TRM-01 should always be grounded through the protective earth
lead of the power cable in AC installations, or via the ground connection for DC
installations.
The line fuses for the TRM-01 are located on the Power Module units
themselves. Access to the fuses requires removal of the Power Module card.
The fuse, a 20mm type, is located in the fuse holder labeled "F1". Make sure
that only fuses of the same rating are used for replacement. Do not use repaired
fuses or short-circuit the fuse holder.
Figure 2-2 : Fuse Location on AC Power Module
Line
Fuse
Holder
Location
Power
Module
(one or two)
Mains
Switch
in back
TRM-01
Chassis
Chapter 2. Installation
11 TRM-01 APR 2000
2-4-2. Rear panel connectors
The FT1 Cards install into the front of the TRM-01 and receive DC
power from the back plane or “main board”. The back plane provides both DC
power to the T1 Cards and routes signals from the cards to the T1 (CSU) and
data port (DSU) connectors accessible at the rear of the TRM-01. Three
interface connector groups are provided for each slot. The T1 signals may use
either the Rx/Tx BNC pair for unbalanced transmissions or the 5pin Molex
connectors with terminal block adapters for balanced transmissions. The data
port connections are made with optional adapter cables, using a common panel
connector, HDB26F for all interfaces.
Figure 2-3 : TRM-01 Rear Panel Connections
HDB26F Data Port
T1 unbalanced BNCs
T1 balanced Molex
HDB26F to RJ-45
(
for FT1/ET10
)
Molex to terminal
post adapter
Alarm Relay Contacts
Mains Switch
IEC AC Mains Input
Chapter 2. Installation
12 TRM-01 APR 2000
2.5 Power Supply Modules
The Power Supply Modules in the TRM-01 are available in two
versions, AC or DC. The AC version supports input voltages of 90 to 250 volts
at frequencies of 50 to 60 Hertz. The DC version supports –42 to -54VDC input
voltage. Only one power supply module is required to power a completely full
rack. When two Power Supply Modules are installed, the supplies are hot
swappable, meaning any one supply may be removed and replaced without
impacting the operation of the TRM-01 Rack.
When an AC Power Module is used in the TRM-01, AC power enters
from the IEC mains input connector on the rear panel. AC power is supplied to
the AC Power Module card(s) when the mains toggle switch is closed. The AC
passes through the F1 fuse(s), located on the Power Module card(s). The AC
power is rectified and filtered before being passed to the regulator module. The
regulator module is factory adjusted to provide 48VDC to the back plane with
complete regulation and over-voltage, over-current, and over-temperature
protection.
When a DC Power Module is used in the TRM-01, DC –48V enters from
the terminal block on the rear panel (see Figure 2-4). DC power is supplied to
the DC Power Module card(s) when the mains toggle switch is closed. The DC
passes through the F1 fuse(s), located on the Power Module card(s). The DC
power passes through the rectifier and filtering circuits, which provide reverse
polarity protection before being passed to the DC-DC regulator module. The
regulator module is factory adjusted to provide 48VDC to the back plane with
complete regulation and over-voltage, over-current, and over-temperature
protection.
Figure 2-4 : DC Model Power Connection
3-pole terminal block
for –48VDC Input
plus Frame Ground
Mains Switch
Chapter 3. Data Modules
13 TRM-01 APR 2000
3.1 Data Module Overview
The Data Modules for the TRM-01 are FT1 (fractional T1) Cards which
slide into the TRM-01 chassis, and interface with the pack panel “main board”.
The back panel provides an interface connection to the FT1 cards for power,
T1 connection, data port connection and control logic (for optional SNMP/local
management terminal). The cards are designed to be “hot” swappable, meaning
the TRM-01 chassis need not be powered off in order to replace a card or pull it
for configuration setting. Each FT1 Card has a protection fuse and its own on
card DC-DC regulator. Each FT1 Card in the TRM-01 receives the DC buss
48VDC and uses its own on-card DC to DC converter to derive the required
operating voltage of 5VDC. Removal and installation of FT1 cards with the
rack chassis under power will not effect the operation of other FT1 cards. The
one exception to this would be a case where the improper fuse (rated too high)
were placed on a defective FT1 card, causing the main AC or DC power
module's fuse(s) to open. It should also be noted, that the FT1 cards themselves
have no redundancy. Therefore, if a card is pulled from the chassis while the
communication link is active, the link will be broken.
Removal of an FT1 Card is accomplished by loosing the two (2) captive
screws on the face plate of the card module, and then pulling the card straight
out of the chassis with the same screws. Apply equal pulling force to both top
and bottom captive screws to avoid the card binding in the rails of the chassis.
(refer to Figure 3-1) Replace the card by reversing the procedure, align in the
slot groove and gently seat the card. Retighten the captive screws.
Figure 3-1 : Removal/Replacement of FT1 Card in TRM-01 Chassis
Captive
Screws
TRM-01
Chassis
Card
Rails
Interface
Connector
FT1 Card
Configuration
DIP Switches
Chapter 3. Data Modules
14 TRM-01 APR 2000
Figure 3-2 : FT1 Card Detail
Push button
switches
for Test
Loop Back
Power, Status
and
Alarm LEDs
9
Interface
Connector
DC-DC
Converter
Power
Protection
Fuse
Configuration DIP Switches
Hardware Version, I/F Type
Chapter 3. Data Modules
15 TRM-01 APR 2000
The FT1 Card in the TRM-01 uses a common bare PC board. During
production, the card assembly is outfitted with the required interface circuitry
and firmware for a particular interface type. A check mark is placed in the box
as noted in the previous figure (shown with V.35 checked). The appropriate
interface adapter cable is then necessary for proper functioning. Care must
always be taken when swapping boards. Always check and match the correct
type. The three board types are RS-530 (public), V.35 and ET10 (Ethernet).
X.21 and RS-449 interfaces are fully supported by adapter cable paired to the
RS-530 (public) card.
There are seven (7) DIP (Dual Inline Package) Switches located along the
top of the FT1 Card numbered DIPSW1~7. The switches functions are to set
the T1 line connection impedance, frame mode, Time Slot allocation, clock
mode, line code, CRC, idle code, and data channel interface rate. Please refer to
Appendix A for the setting tables.
Located on the upper half of the front panel are the indicator LEDs. There
is a green power indicator which will light when the card is placed in an active
chassis. Failure of this LED to light indicates a possible power failure on the
FT1 Card itself. The TD, RD, RTS, and DCD yellow LEDs indicate status of
the data communication port. The red TxCLK, signal loss, sync loss and alarm
LEDs all indicate error conditions on the T1 line or link connection. When loop
back testing is being performed, the red test LED will light. If any bits are
received in error, the red err LED will flash.
Located on the lower half of the front panel are the manual test switches.
The top three switches set the type of loop back test to be performed. The
bottom switch enables the internal pattern generator. The Loc dig loopbk (local
digital loop back) switch tests the performance of the local FT1 Card, the
remote unit and the connections between by looping back the T1 received data
to the remote unit. The Loc ana loopbk (local analog loop back) switch tests the
performance of the local FT1 Card, the data terminal device and the
connections between by looping back the received terminal’s data back to the
terminal. The Rem loopbk (remote digital loop back) switch tests the
performance of the local and remote units, as well as the line, by issuing a
proprietary loop back command to the remote CSU/DSU. In order to perform
remote loop back, the FT1 Card must not be in unframed mode. When the
Pattern switch is depressed, the local FT1 Card sends out a 511-bit test pattern
(according to ITU-T V.54) on the T1 link, enabling testing of the entire link.
Refer to Chapter 4 for detailed diagrams of the loop back functions of the TRM-
01’s FT1 Card.
Chapter 3. Data Modules
16 TRM-01 APR 2000
3.2 Data Module LED Indicators
PWR: This green LED should be lit when the chassis is
powered and the FT1 Card is seated in the rack slot.
TD: This yellow LED will flash when there is transmit data
activity from the connected DTE equipment to the FT1 Card.
RD: This yellow LED will flash when there is receive data
activity from the FT1 Card to the connected DTE equipment.
RTS: This yellow LED will be lit when the Request To Send
signal is active on the data port.
DCD: This yellow LED will be lit when the carrier signal is
active between the DSU and the connected DTE equipment.
TxCLK Loss: This red LED will light in the event of CSU
clock signal loss.
Sig Loss: This red LED will light in the event of CSU signal
loss.
Alarm: This red LED will light in the event of the following
alarm conditions: Remote Alarm Indication (RAI), Bi-Polar
Violation (BPV) error, All ones (AIS), CRC4 error, or Frame
Slip.
Err: This red LED will flash upon receiving an error while in
BERT mode (pattern depressed and looped back).
Test: This red LED will light if any of the test pushbuttons are
depressed or if the FT1 Card is in analog loop back due to
reception of a V.54 remote loop back code from the remote unit.
Figure 3-3 : FT1 Card face (RS530 public
card for RS-530, X.21, or RS-449)
FT1
/
