As per Federal Communications Commission Rules concerning radio frequency emissions, this
device complies with FCC Part 15, Subpart J for class A computing devices.
This device generates, uses, and can radiate radio frequency energy and if not installed
in accordance with the System Practice, may cause interference to radio communications.
It has been tested and found to comply within the limits for a class A computing device
pursuant to Subpart J of Part 15 of the FCC Rules 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
Electrostatic discharge ( ESD ) results from the buildup of static electricity and can cause
damage to electronic components. ESD precautionary practices are required when installing,
configuring, or repairing this device. Use of a wrist strap is recommended. Do not use
conductive tools to change parts or jumper settings in this device.
This Class 2 data communications equipment has been Level 3 NEBS compliance tested and approved
under the guidelines specified by the Bellcore GR-63-CORE, and Bellcore GR-1089-CORE Technical
References. The CO SAM conforms to the UL Standard for Safety, ANSI/UL 1950, Third Edition.
The manufacturer warrants that this equipment is free from defects in materials and workmanship.
The warranty period is five years from the date of shipment. The manufacturer's obligation under
this warranty is limited to the repair or replacement of the defective equipment provided it is
returned, shipping prepaid, within a reasonable period of time. This warranty shall not apply to
equipment that has been subject to accident, misuse, alterations, or repairs not made or authorized
by the manufacturer.
This publication and the equipment it describes contain proprietary information. No part of
this document may be copied or reproduced in any form without permission from the manufacturer.
The information in this document is subject to change without notice. The manufacturer assumes
no responsibility for damages resulting from the use of this document, including but not limited
to, lost revenue, lost data, or other damages.
For technical support call 1-800-881-8202.
TABLE OF CONTENTS
The Dual Modem Single Channel Multiplexer (DMSCM) provides connectivity redundancy through
manual or automatic switch-over in the event of a facilities loss. The I/O card was engineered
to be compatible with two Lucent BNS/VCS Datakit trunk cards (T1 and SAMSL). It incorporates
(2) internal 56KB DDS modems that are monitored and controlled by an embedded CPU that
automatically switches from the primary circuit to the backup circuit in the event of a
The monitor program watches for both loss of carrier and data mode idle (no valid data being
received). If the condition is present on the in-service line, the CPU checks the backup
line condition and switches from primary to backup. When the primary line failure clears,
the CPU will automatically restore the connection to primary. If either the primary or
backup line fails, the monitor program will provide a contact closure alarm point for the
failing line. This scan point alarm is jumper configurable for normally open or normally
- Two internal modems provide online/backup redundant functionality.
- A three (3) position hardware switch provides:
- manual select primary
- manual select backup
- auto mode(CPU controlled)
- Two alarm points are provided to alert Primary or Backup failures. These contact closure
points are jumper configurable for normally open or closed operation.
- One console port is provided for remote or local access. This allows for system
configuration, remote switching between primary and backup lines and system status
reports. The port is RS232 9.6 baud 8 bit data 1 stop bit/no parity. The port is
password protected and time out protected for added security.
- Loop back functions are performed through console port commands and/or manual
operation of physical loopback switches on the I/O circuit card.
- Default modem operation is 56K baud DDS internal clocking.
2. Product Description
- CPU operating 16. MHz
- 20k Flash Memory
- 128 bytes direct data address space (DATA)
- 128 bytes indirect data address space (IDATA)
- 128 bytes serial flash memory to save configuration parameters
- Two Level-1 Modems connected via leased lines. (non-dialing modems)
- Operation mode is "56Kbit DSU Internal"
- 9.6 Kbs, 8-Data , 1-Stop bit, NO Parity.
3-Way default modem selection
- Used for complete HW reset for DMSCM Modems and the Serial Port.
3. Functional Block Diagram
The DMSCM connects the Datakit I/O channel and one of two analog DDS lease lines via the
internal modems. The 3-Way toggle switch provides additional control over the modem selection.
Only one line can be connected to the channel at any given time.
4. Line Channel Connection Procedures
Line selection procedure
- Factory default settings use the Primary Modem as the Primary and the Backup Modem as the Backup.
- A 3-Way hardware switch is provided to change the modem selection. If this switch is moved to
either the Middle (Backup Modem) or upper (Primary Modem) position, forced modem selection
mode is active. While the manual switch is in either of these two positions the console
command MT (modem toggle) will have no effect, the modem manually selected will remain
connected to DMSCM. Therefore, if the DMSCM is manually switched to an out of service
line the SAM or TRUNK will be inoperative. Manual selection overrides CPU monitoring
- Local DMSCM card's "Default Modem" line should be connected to remote DMSCM
card's "Default Modem". This means if the local default modem is Primary,
the remote location should be connected to its default Primary on the DDS trunk
facilities. If cross wiring exists, corrective action should be taken using the
modem switch procedure.
- "Default Modem" switch-over procedure; After logging on to the DMSCM console,
type "MS" (modem switch) command. This will switch "Default Modem"
selection from Primary to Backup or vice versa. Verify the result with "SH"
- Modem toggle procedure; When both modems are in their Connected and Ready states
respectively, the "MT" (modem toggle) command will toggle the connection
from "Connected Modem" to "Ready Modem". After a reset the original
"Default Modem" selection will be applied. Consecutive "MT" commands
will force the connection to alter. NOTE: The "MT" command will only function
properly from the Master DMSCM.
5. Console and Modem Connectivity
Serial Port (Console) and Modem Wiring Diagrams
NOTE: The Serial (Console) Port can be connected to a TY12 via an eight wire RJ45
to RJ45 straight through cable to facilitate remote access capability.
Default line selection and wiring
6. DMSCM Toggle Switch, LEDs, and Jumper Configurations
Toggle Switch Operation
The hardware three (3) position toggle switch on the DMSCM will ship in the 'AUTO' position.
In this position the default modem will be the 'Primary Modem'. During normal operation the
DMSCM in both the remote and local devices should be left on this setting. Auto Operation
allows the resident CPU to constantly monitor the condition of the facilities and verify the
stability of the connection. Should a modem or line failure occur, the CPU switches over to
the Backup resources. This switch-over occurs in less than one (1) second and does not cause
a trunk fade. When removed from the 'AUTO' position (into either the Primary or Backup
position), the DMSCMs' resident CPU is overridden. The toggle switch should only be taken
out of the 'AUTO' position for maintenance and trouble clearing operations. Please refer
to the diagrams below for proper toggle switch operation.
This is the 'Normal' or 'Default' Operation of the DMSCM. Both the Local and the
Remote Switches are in the 'AUTO' position. This allows the resident CPU to utilize
and monitor the Primary facility. In the event of a modem or facility failure the
CPU will switch over to the Backup modem and facility.
With one end in 'AUTO' and the other end in 'BACKUP', the CPU is overridden and the
DMSCM will default to the Backup facility and modem. This configuration may be employed
when the Primary facility is to be taken out of service for maintenance or trouble
clearing procedures. NOTE: With one end in 'AUTO' and the other end in PRIMARY,
the CPU is again overridden and the DMSCM will default to the Primary facility and modem.
With one end in PRIMARY and the other end in BACKUP, the DMSCM is not operational.
Normal operation requires that the toggle switches be left in the 'AUTO' position
except for maintenance and trouble clearing purposes.
Six LEDs are provided on the DMSCM to facilitate visual operational status of both the
modems and the facilities. The top three (3) LEDs monitor the status of the Backup
facility and modem, while the middle three (3) LEDs monitor the Primary facility and
modem. The bottom pair of LEDs indicate which modem/facility is active. Please refer
to the diagram and matrix below.
The DMSCM provides two (2) Scan Point Alarm Jumpers. If either the Primary or Backup
facility fails, the monitor program on the internal CPU will provide a contact closure
alarm point for the failing line. This scan point alarm is jumper configurable for
'normally open' or 'normally closed'. The DMSCM ships with the jumpers in the 'normally
closed' position. The jumpers are located on the DMSCM. They are labeled 'JMP1' which
is associated with the Primary modem and 'JMP2' which is associated with the Backup modem.
There is an additional Timing Jumper that MUST be shorted when the DMSCM circuit card is
used in conjunction with a TN1392 T1-Trunk in the SAM. The jumper should be removed when
used with any other circuit card. See the diagram below for jumper locations and settings.
For Console connectivity to a TY12 module, the DTR Jumper MUST be shorted. Leave open in
all other applications.
7. Console, Configuration, and Diagnostic Commands
The DMSCM provides a password protected serial port interface for local or remote
console configuration, testing, and status report generation. The. Console Serial
Port has an RJ45 type connector and is configurable for 9.6 KB, 8 bit, 1 stop. The
port is also 'time out' protected. The following pages contain the user available
card control commands. The default password is 'cbm'. It is recommended that the
password be changed after the product is installed.
Configuring from the terminal display
Boot screen, Logging on and out and command line
After the DMSCM startup the user may login at the PSWD prompt by entering the initial password 'CBM'.
The screen below is only observed right after pressing the reset button, upon initial power
up, or after executing the RESET 'RE' Command. The Version Number and the CBM USA Product
ID of the DMSCM are important parameters for trouble reporting and problem resolution with
CBM customer service representatives.
The Command Prompt
The "IM1000:" prompt is an indication that the DMSCM is ready for input commands.
Invalid commands are responded to by an audible "BEEP" or with a text display
describing the cause for the error. The command line display format is shown below.
CP - Change password
Password access is required to configure the DMSCM. Sessions stay active as long as
there is keyboard activity. The session will drop in the absence of keyboard activity
after 200 seconds. This timing parameter is user configurable. The user is allowed
to change the password after a double verification sequence of two identical entries
up to 8 characters. The password is not case sensitive and alphanumeric characters
are allowed. If the password is correctly typed twice it is accepted and modified
Default password is set to CBM when card is shipped.
The DCSCM cards operate in a Master/Slave relationship. Use the SET 'S' command to
program the Node side as 'Master' and the SAM side as 'Slave'. Use the MS (Modem Switch)
command to set the Primary and Backup modems. The SAM side and the Node side MUST match
for proper operation. Use the MODEM 'M' command to set the desired facility timing mode
(see the Help Modem Menu 'HM' for options). Verify the settings using the SH (Show)
command (see the following page). When the primary modem displays the 'CONNECTED'
status, and the Backup modem displays the 'READY' status, the DCSCM is ready for operation.
At this point you may download the SAM, provided that the hardware cables and jumpers have
been properly configured.
SH - Show DMSCM status
This command shows the current status of all logical and physical entities in DMSCM card
which include the Default Modems, Master and Slave Setting, LED(s), Timers, and the
Status and Connection Type.
HE- Help request, syntax errors or unrecognized commands
The General Help Menu 'HE' display is shown if an unrecognized command is
entered in command line or if the return key is entered with no command.
DCSCM Loopback Commands
The DCSCM comes equipped with a resident Remote Loopback Feature that allows the user to
test the health of the facility on either of the modems without service interruption. The
Remote Loopback Feature is initiated from the Console Command Prompt (IM1000) and executes
a data looping routine to determine the status of the facility (see below). If the active
line is chosen for the Remote Loopback Diagnostic the DMSCM will query the user and require
a YES or NO response to continue so as not to affect any active traffic. After completion
of the diagnostic, the DMSCM takes the loop down and returns to normal operation. Use the
Help Test 'HT' command to view diagnostic parameters.
CSU/DSU Loopback Commands
The DMSCM CSU/DSU Loopback utilities are to be used with diagnostics resident to the
Datakit Node. However, they may also be used when conducting diagnostic routines with
the Test Bureau on suspect facilities. Both the CSU and the DSU Loopback commands
initiate a loopback condition that directs data AWAY from the initiating device (i.e.
A CSU Loopback command executed on the SAM DMSCM will loop the facility back to the
Datakit Node). The loopback condition remains in place until manually removed (see below).
The CSU Loopback command directs data back prior to entering the resident modem logic.
The DSU Loopback Command directs data back after utilizing the modem logic. A CSU/DSU
LOOPBACK CONDITION ON THE ACTIVE CIRCUIT WILL INTERRUPT TRAFFIC AND CAUSE A TRUNK FADE.
CAUTION SHOULD BE EXERCISED WHEN USING THESE COMMANDS!
DMSCM Loopback Switches
CSU Loopback Switches
The DMSCM is equipped with two (2) toggle switches that can be utilized to initiate a
CSU Loopback state. This is the same condition that results from a console initiated
CSU Loopback Test. The switches are delivered in the standard operating position,
which is to the left and labeled 'NORMAL'. To place the DMSCM in the Loopback Mode,
move the desired circuit switch to the right 'LOOPBACK' position. The Looped condition
remains until the switch is returned to the 'NORMAL' position. A CSU LOOPBACK CONDITION
ON THE ACTIVE CIRCUIT WILL INTERRUPT TRAFFIC AND CAUSE A TRUNK FADE. CAUTION SHOULD BE
EXERCISED WHEN OPERATING THESE SWITCHES!
Local Loopback Testing
The DMSCM was designed to utilize the included RJ45 Loopback Plug in conjunction with the
Datakit resident SAMTRK diagnostic. The Loopback plug is inserted into the desired modem
port and the SAMTRK diagnostic is run in the 'near_dsu' mode. No loopback switches need
to be operated and no DMSCM commands are required to execute the SAMTRK Datakit diagnostics.
The Loopback plug can be easily manufactured by joining leads 1 to 7 and leads 2 to 8.
The DMSCM will upon detection of a facility failure and subsequent switchover generate
the following Datakit alarm messages when installed in a CBM Enhanced SAM64. The first
Alarm Message will appear only indicating that the Alarm Grid has been activated. The
second message will appear every five minutes until the alarm is cleared. NOTE: When
the DMSCM is installed in a CBM Enhanced SAM128 only the second Alarm Message will be
Along with the Datakit Alarms, the DMSCM also has an audible and a visual alarm on the front panel
of the CBM Enhanced SAM64 and the SAM128.
ALARM NOTES: A Facility Failure will activate the Red FAULT Light as well as activating
the Audible Alarm. The Audible Alarm can be silenced by operating the rocker style Cutoff
Switch. Doing so will illuminate the Yellow OFFLINE Alarm Indicator.
The DMSCM will report Error Messages on the 'SH' (show status) page (see below).