General DataComm Megamux Plus 036M241 Specifications

ATTENTION!
STATIC SENSITIVE DEVICES
PROPER HANDLING AND GROUNDING
PRECAUTIONS REQUIRED
This equipment contains electrostatic sensitive devices. Use ESD pre-
cautionary procedures when removing or inserting parts or printed
circuit (pc) cards. Keep parts and pc cards in their antistatic packaging
material until ready to install.
The use of an antistatic wrist strap, connected to the grounded
equipment frame or chassis, is recommended when handling pc cards
during installation, removal, or setting of on-board option switches. Do
not use a conductive tool, such as a screwdriver or paper clip, to set
the position of the option switches.

MEGAMUX PLUS
7,0(#',9,6,21#08/7,3/(;(5
(GDC PART NO. 036M241)
This product was designed and manufactured by
General DataComm, Inc. (GDC)
Middlebury, Connecticut 06762-1299

WARNING
This equipment generates, uses, and can radiate radio frequency energy and if not
installed and used in accordance with the instruction manual, may cause
interference to radio communications. It has been tested and found to comply with
the limits for a Class A computing' device pursuant to Subpart J of Part 15 of FCC
Rules, which are designed to provide reasonable protection against such
interference when operated in a commercial environment. Operation of this
equipment in a residential area is likely to cause interference, in which case the
user at his own expense will be required to take whatever measures may be
required to correct the interference.
CRC-REQUIRED NOTIFICATION
This equipment is a Class A digital apparatus which complies with the Radio
Interference Regulations, CRC c.1374.
PUBLICATION NOTICE
This manual has been carefully compiled and checked for accuracy. The
information in this manual does not constitute a warranty of performance.
Furthermore, GDC reserves the right to revise this publication and make changes
from time to time in the content thereof. GDC assumes no liability for losses
incurred as a result of out-of-date or incorrect information contained in this
manual.
READERS COMMENTS
Comments regarding this manual should be addressed to:
Publication Department
Tech Center
General DataComm, Inc.
Middlebury, Connecticut
06762-1299
PROPRIETARY NOTICE
This publication contains information proprietary and confidential to General
DataComm, Inc. Any reproduction, disclosure, or use of this publication is
expressly prohibited except as General DataComm, Inc., may otherwise authorize
in writing.
Copyright, General DataComm, Inc., 1991

Rev. 4, October 1986
FCC-REQUIRED NOTIFICATION
FOR USERS OF FCC-REGISTERED EQUIPMENT
Read before using this technical manual or installing subject equipment.
This equipment complies with Part 68 of the Federal Communications Commission (FCC) Rules and
Regulations. Connection of data communication equipment to the public telephone network is regu-
lated by the FCC Rules and Regulations. These regulations require:
A. All connections to the telephone network must be made through standard plugs and telephone
company provided jacks or equivalent.
B. Connection of this equipment to party lines and coin telephones is prohibited
C. If the telephone company asks you what equipment is connected to the telephone line, tell them to
which line the equipment is connected, and give them the FCC Registration number and Ringer
Equivalence number of the equipment. These numbers can be found on a label located on the
back of the front panel on all DataComm-type equipment and on the underside or rear panel of
other equipment.
D. If you experience trouble, disconnect the equipment from the telephone line to determine if the
equipment is malfunctioning. If it is, remain disconnected until the problem is corrected. Should
this equipment cause harm to the telephone network, the telephone company may discontinue
your service temporarily. If possible they will notify you in advance. But if advance notice is not
practical, you will be notified as soon as possible. You will be informed of your right to file a
complaint with the FCC.
E. The telephone company may change its communication facilities, equipment, operations, and
procedures where reasonably required for operation. If this occurs, the telephone company will
notify you in writing.
F. IL is the user's obligation to notify the telephone company prior to disconnecting equipment
from 1.544 Mbps digital service.
G. According to Part 68 of the FCC Rules and Regulations, customers are not authorized to repair or
modify this equipment. Any repair or modification will null and void the FCC registration and the
warranty of this equipment.

CANADIAN DEPARTMENT OF COMMUNICATIONS (DOC) REQUIRED
NOTIFICATION
FOR USERS OF DOC-CERTIFIED EQUIPMENT
Read before using this technical manual or installing subject equipment.
The Canadian Department of Communications label identifies certified equipment. This certification
means that the equipment meets certain telecommunications network protective, operational, and safety
requirements. The Department does not guarantee the equipment will operate to the user's satisfaction.
Before installing this equipment, users should ensure that it is permissible to be connected to the facili-
ties of the local telecommunications company. The equipment must also be installed using an acceptable
method of connection. In some cases, the company's inside wiring associated with a single line individual
service may be extended by means of a certified connector assembly (telephone extension cord). The
customer should be aware that compliance with the above conditions may not prevent degradation of
service in some situations.
Repairs to certified equipment should be made by an authorized Canadian maintenance facility desig-
nated by the supplier. Any repairs or alterations made by the user to this equipment, or equipment mal-
functions, may give the telecommunications company cause to request the user to disconnect the
equipment.
Users should ensure for their own protection that the electrical ground connections of the power utility,
telephone lines, and internal metallic water pipe system, if present, are connected together. This pre-
caution may be particularly important in rural areas.
Caution: Users should not attempt to make such connections themselves, but should contact the appro-
priate electric inspection authority, or electrician, as appropriate.

036R660-E1
(55$7$#6+((7
FOR
MEGAMUX PLUS TDM
OPERATOR'S INSTRUCTIONS
Publication No. 036R660-000, Issue 9
OVERVIEW
The VLBRV (Very Low Bit Rate Voice) or VLBRV/FAX Channel Module is an analog voice
channel card for the MEGAMUX PLUS TDM. It provides voice encoding algorithms that max-
imize voice channel bandwidth utilization while offering low bit rate values of 9600, 4800 and
2400 bps. The VLBRV Channel Module is used in transmission applications to maximize avail-
able bandwidth. Applications include use in digital services such as ASDS (FT-1), ADN, satellite
and in feeder applications in which a customer needs to integrate both voice anddata. Voice com-
munication is two-way simultaneous (full duplex). The VLBRV Module mountsinto the MEGA-
MUX PLUS channel or expansion shelf.
This errata sheet covers all aspects of the VLBRV Channel Module configuration, diagnostics,
alarm and status scans as seen on the MEGAMUX PLUS supervisory controller screens.
DEFINING VLBRV CHANNEL PARAMETERS
Channel parameters are selected in a logical sequence. You must first specify the number of the
channel that you wish to configure. Once a channel number is selected, you enter the voice chan-
nel type. Once a channel type is selected, there are a range of parameters to be selected. You are
not allowed to select these parameters until a channel type is specified. Figure 1 shows how the
VLBRV channel parameters are configured.
FIGURE 1. CHANNEL PARAMETERS
Channel Number
The channel number associates a set of channel parameters with a VLBRV Channel Module in
the MEGAMUX PLUS TDM shelf. The channel number is determined by the positionof the VL-
BRV Channel Module in the shelf. Channel numbers range from 1 up to a maximum of 54 (you
must have one expansion shelf for a system with up to 38 channels, and two expansion shelves
for a 54-channel system).
CURRENT PARAMETERS FOR CHANNEL #01 CONFIGURATION AM
CHN CIRCUIT CIRCUIT BAUD T-R CLK TID-IR OR VF-DB-LEVEL I/F TID
# TYPE NAME RATE M/S DATA STOP M S TYPE MODE/DELAY
01 VLBRV MIKE1 9.6K ___ ___ 0.0 0.0 VC_1 ___

036R660-E1
2
Circuit Type
The circuit type entry defines the type of voice signal that the channel multiplexes. The selection is
determined by the equipment connected to the channel. The circuit type must also be supported by
the VLBRV Channel Module associated with the channel number. The VLBRV Channel Module
receives and transmits VF (Voice Frequency) signals. A primary task of the VLBRV Channel Mod-
ule is to convert input voice to a synchronous format, and convert output data to the original voice.
When using the VLBRV Channel Module, the circuit type is VLBRV or VLBRV/FAX.
Circuit Name
The VLBRV channel may be assigned a circuit name. This name is associated with the channel, and
appears in configuration, status, and diagnostics displays. Status and diagnostic routines that in-
volve the channel may be invoked by circuit name as well as circuit number.
Baud Rate
A baud rate is specified for every MEGAMUX PLUS channel. When a configuration is activated,
the TDM sends the entered baud rate to each VLBRV Channel Module which selects the proper
tinning signal from the MEGAMUX PLUS clock bus. For the VLBRV Channel Module, you can
select either 9600, 4800 or 2400 bps.
Transmit-Receive Clock
Not used on the VLBRV Channel Module.
TID-IR or Data/Stop Bits
Not used on the VLBRV Channel Module.
VF dB Levels
The output level of the VLBRV Channel Module is selected as a channel parameter. The level may
be specified in arange of +1.5 dB to-6.0dB, with 0.5 dB between each level (a total of 16 selectable
levels). Output levels are selected separately for Node M and Node S channel outputs.
This level is an adjustment to an absolute output level selected on the VLBRV Channel Module.
The output level is set to 0 dBm or +7 dBm by the position of a DIP switch. Generally, that switch
is set according to the requirements of the PBX or voice termination system to which the VLBRV
Channel Module is connected. The setting of this parameter adjusts the voice output above orbelow
the level set by the switch, to compensate for cable attenuation which offset the proper output levels
of the VLBRV channel. You may change this level as part of the Diagnostics routines. The Rcv dB
routine allows you to make the same level selections that are made when configuring the VLBRV
Channel Module. When either routine is complete, the controller asks whether changes to the output
levels should be changed. If changes are saved, the dB level entry for that channel configuration is
changed. This change occurs for the specified channel number in all stored configurations where
the channel is still configured far voice.

3
036R660-E1
Alarm Cut-Off (ACO)
The VLBRV has the capability to generate alarms indicating failures related to the VLBRV
Channel Module's operation. Alarms are indicated through front panel indicators, messages dis-
played in the system alarm scan, or by the VLBRV Channel alarm scan. When alarm cut-off
(ACO) is selected, the VLBRV Channel Module cannot report alarm conditions to the system.
ACO is useful when an alarm condition has been noted, but the VLBRV Channel Module con-
tinues to generate alarm messages. When ACO is implemented, it prevents further messages from
entering the Alarm Scan displays and filling message buffers. This ensures that the alarm scan
reports only new alarms, and reflect only new problems that occur in the network. When the VL-
BRV Channel Module is set for ACO, the Alarm indicator on its frontpanel remains litto indicate
this condition.
ACO may be selected for all VLBRV Channel Module's in a configuration. This action prevents
the reporting of channel alarms by the alarmscan. The alarm scan listcontains only major alarms
(those that indicate a system-level problem). When ACO is set On for all channels, it cannot be
turned Off again (except in version 3.20 and later) for all channels simultaneously; it may only
be turned Off on a channel by channel basis, or when a change is made to the configuration.
Interface Type (I/F Type )
The VLBRV Channel Module voice interface type arrangement supports E and M signaling. M
is an input control signal (input to the voice channel) and E is an output control signal. The signal
state of an M-lead at one channel interface is multiplexed through the system and transmitted at
the opposite end interface as an E-lead output. The interface type is identified as I/F type VC-1
(shown below).
I/F CONTROL [NAMES]
MODE M NODE S
SEND : M M
RCV : E E
Switches and jumpers on the VLBRV Channel Module selects one of the five E and M signaling
types.Each type is adifferent representation ofthe E and M On and Off statesusing voltage levels
or open and closed circuits. Since any of these types result in On or Off states for the signals, they
are not differentiated by the supervisory port display. You may display and change the states of
the EandM signals using Control State routines providedas part of the Diagnosticsroutines. This
feature allows you to disable the VLBRV Channel Module when required. However, if you save
changes made to the voice channel controls, the control states are changed in the channel config-
urationalso. Besure to notesuch changes ifyou makethem. A disabledVLBRV Channel Module
remains disabled until action is taken through Configuration or Diagnostics routines to restore
them.