OTS MK-7 BUDDY-LINE User manual

Two-Diver Intercom
“Technology in Depth”
User Guide
MK-7 BUDDY-LINE

- NOTICE -
This manual and the information contained herein are provided for use as a
maintenance and operation guide. No license or rights to manufacture, produce,
and/or sell either the manual or articles described herein are given. Undersea
Systems International, Inc., dba Ocean Technology Systems hereinafter referred
to as OTS, reserves the right to change specications without notice. It is
recommended that all users read and fully understand this manual before using
the MK-7 Buddy-Line.
All statements, technical information, and recommendations herein are based on
tests we believe to be reliable, but the accuracy or completeness thereof is not
guaranteed; and the following is made in lieu of all warranties, expressed or implied,
including the implied warranties of merchantability and tness for purpose: Seller’s
and Manufacturer’s only obligation shall be to replace such quantity of the product
proved to be defective. Before using, the user shall determine the suitability of the
product for intended use, and the user assumes all risk and liability whatsoever in
connection therewith. Neither Seller nor Manufacturer shall be liable either in tort
or in contract for any loss or damage—direct, incidental, or consequential—arising
from the use of or the inability to use the product. No statement or recommendation
not contained herein shall have any force or effect unless it is in an agreement
signed by ofcers of the Seller and Manufacturer.
- IMPORTANT SAFETY NOTICE -
(Please read before using product.)
It is absolutely essential that all divers are properly trained and equipped and
fully understand this user’s manual before attempting to use the Aquacom®
MK-7 Buddy-Line.
While the Aquacom®MK-7 Buddy-Line provides divers good underwater
communications, it does not change or eliminate the potential hazards of diving!
© Copyright 2014 by Undersea Systems International, Inc. dba
Ocean Technology Systems. All rights reserved.
Specications are subject to change without prior notice.
P/N 506018-002 A
i
Refer to the Library page of our Web site, www.otscomm.com, for a list of
any changes made to this manual since its publication.

TABLE OF CONTENTS
Section Title Page
1 Introduction........................................................................................1
2 Specications.....................................................................................2
3 Functions & Features.........................................................................3
3.1 Functions.................................................................................3
3.2 Features...................................................................................4
4 Operation ...........................................................................................6
4.1 Setup for the Tender................................................................6
4.2 Setup for the Diver(s)..............................................................6
5 Batteries ...........................................................................................10
6 Troubleshooting ...............................................................................11
7 Maintenance.....................................................................................12
8 Helpful Hints ...................................................................................13
Warranty Information.......................................................................................14
Important Safety Notes .............................................................. i, 3–4, 8, 12, 13
1
SECTION 1
INTRODUCTION
Congratulations! You have just purchased the nest, state-of-the-art hard-wire
intercom in the world. Your new MK-7 Buddy-Line two-diver air intercom
represents state-of-the-art technology and innovation—the choice of discriminating
divers throughout the world. Please take the time to read this user guide. With proper
care and use, your OTS product will provide you with the ultimate in high-quality
communications and reliability.
The MK-7 Buddy-Line is a compact, self-contained two-diver air intercom providing
clear communications between the operator and diver(s). The MK-7 Buddy-Line
offers four-wire (round-robin or open-microphone) type communications.
This manual will cover specifications, operating instructions, four-wire
communications, batteries, helpful hints, and warranty information.
These guidelines and illustrations are presented to assist you. If you need additional
information, do not hesitate to confer with your local OTS dealer or representative.
If you require service, contact us:
Undersea Systems International, Inc., dba
Ocean Technology Systems
3133 W. Harvard Street, Santa Ana, California, 92704 USA
Toll-Free: [phone] • Tel.: [phone] • Fax: [phone]
E-mail: [email protected]
World Wide Web: http://www.otscomm.com

SECTION 2
SPECIFICATIONS
Input Voltage: 12 VDC
Input Current: 600 mA peak
Idle Current: 30 mA
Frequency Response: 600 Hz to 10 kHz
Microphone Type: Dynamic
Power Output: 2 watts RMS
Battery Type: Eight AA alkaline batteries
Battery Life: 12 hours (normal use) using eight AA alkaline batteries
Housing: Injection-molded, high-impact plastic
Size: Height: 6.750 inches from bottom to top of connector
Width: 4.250 inches from latch to latch
Depth: 2.750 inches from front knob to rear buckle
Weight: 1.0 pounds, without batteries
ComCable/ComRope: Up to 1200 feet
2

SECTION 3
FUNCTIONS & FEATURES
3.1 FUNCTIONS
The MK-7 Buddy-Line hard-wire system utilizes the “four-wire” approach. It is a
closed loop comparable to a telephone system. A typical hard-wire system consists
of a surface intercom, a headset with a boom microphone, a ComRope (set up for
four wires, shielded or true spiral four), a diver microphone-earphone assembly,
a mask microphone, and some sort of diving mask with accommodations for a
microphone. The Interspiro Divator MKII “AGA” full-face mask (FFM) is what
most professionals prefer, according to our statistics. A hard-wire system requires
a physical connection (i.e., umbilical/ComRope) between the listener and talker.
The signal travels over the communication ComRope.
Most hard-wire intercoms can be congured for either two- or four-wire operations.
Four-wire communications is dened as a duplex communication route. Two wires
provide the uplink signal path, and two additional wires provide the downlink path.
Thus everyone can be online simultaneously (similarly to a telephone conference
call). Since the diver is never cut off the diver while talking, as is the case with
a two-wire system, the four-wire system is the safer of the two congurations.
Due to the increased efciency achieved with a four-wire system (duplex) and its
simplicity of use, the MK-7 is designed for four-wire operation only.
The standard MK-7 conguration functions as follows: After the system is powered
up and all connections are properly made, the tender’s speech is picked up by the
boom microphone located on the headset. The voice is amplied by the upper
electronics module and routed through the ComRope. Connected to the ComRope at
the diver’s end is the earphone-microphone assembly (typically an EM-OTS-2 for
the new Guardian FFM or EMA-2 for the Interspiro FFM). The tender’s speech is
reproduced by the earphone part of the assembly. When the diver speaks, his voice
is picked up by the mask microphone located inside the mask being used. The voice
is routed through the ComRope, received by the upper electronic module, amplied,
and then routed to the tender’s headset. If a second diver is on-line, he will hear and
talk as well in the same manner. The volume of the tender and diver(s) is controlled
by separate volume controls on the outside of the upper electronics module.
- IMPORTANT SAFETY NOTES -
It is extremely important that the divers are dressed out in a manner that will
strain-relieve the ComRope. Commercial dive schools typically instruct students
to have the ComRope tethered to the diver’s harness or buoyancy compensator
with a quick release. If someone pulls on the ComRope and the diver loses control
of the ComRope, the pull is on the harness, not on the diver’s mask. This setup
prevents accidental removal of the diver’s mask.
3

FIGURE 1: MK-7 Buddy-Line
Additionally, the divers should be dressed out to allow a quick disconnect from
the ComRope to allow for a situation where a diver must free himself from the
ComRope.
In the event divers and the surface tender lose voice communications, both should
have in place a back-up rope-pull system for communication. See Table 1 (p. 9)
for the line-pull system recommended by OTS.
4
3.2 FEATURES
See Figures 1 and 2 for an exploded view of the MK-7 Buddy Line system.
Note: The ComRope can be set up for many types of diving masks and/or
earphone-microphone assemblies. If you are not sure what to order, consult
an OTS dealer or OTS directly for the conguration you require.
1. Headset with boom microphone
2. Noise-canceling boom microphone
3. Female Amp connector
4. Record-out plug (male mini, line level)
5. Small o-ring
6. Male Amp connector
7. Gripper ring
8. Female Amp connector (for ComRope)
9. Upper electronics module
10. Tender volume control
11. Diver 1 and Diver 2 volume controls
12. Housing’s large o-ring
13. Battery pack contacts (copper plating)
14. Eight-cell battery pack (SCB-1)
15. Stainless steel latch
16. Lower housing (battery compartment)

5
Ear-Microphone Assembly
ComRope Assembly
FIGURE 2: ComRope & EMA-2 assemblies
17. Male Amp connector (ComRope)
18. ComRope Assembly
19. Hi-USE®connector (goes to ComRope)
20. Hi-USE
®
connector (goes to diving mask)
21. EMA-2 ear-microphone assembly for AGA

SECTION 4
OPERATION
Before operating the MK-7, make certain the batteries are fresh (see Section 5,
Batteries). Ensure that all o-rings are in place and free of debris or foreign matter.
Verify that all connections are securely fastened. Ensure the divers are dressed in
such a manner that the umbilical/ComRope will not snag. These procedures should
be performed before each dive.
After you have completed the above steps, proceed as follows:
4.1 SETUP FOR THE TENDER
4.1.1 Place the headset with boom microphone on your head so the two
earphones are comfortably over your ears and the boom microphone is
within 1/4 inch of your lips.
4.1.2 Connect the headset’s Amp connector to the upper electronics module’s
Amp connector (Fig. 1, #3 & 6).
4.1.3 Locate the Amp connector on the ComRope, and mate it to the Amp
connector located on the top of the electronics module (Fig. 1, #8 and
Fig. 2, #17). If there is a second diver, do the same for his connection.
4.1.4 Secure the MK-7 to your belt (or wherever is most comfortable) by using
the belt clip located on the back of the upper module.
Note: We recommend that the MK-7 main module have some sort of strain relief
at the tender’s end to keep the diver and/or ComRope from putting excess strain
on the connectors. Excess strain on the connectors would cause damage to the
MK-7 and/or loss of communications.
4.2 SETUP FOR THE DIVER(S)
4.2.1 Although the MK-7 Buddy-Line can be used with various full-face or
mouth masks, the mask most commonly chosen is the Interspiro Divator
MKII (“AGA”) full-face mask (FFM). The following are the setup
procedures, if you have an AGA FFM. You should have already connected
the headset and ComRopes if you are following this manual (see Section
4.1, Setup for the Tender). We are also assuming you ordered and have
the ComRope set up for four-wire communications with a male Amp
connector on one end and a Hi-USE®connector on the other end.
4.2.2. The AGA FFM should already have the EMA-2 earphone-microphone
assembly installed. If not, install it per the installation instruction sheet
provided with the EMA-2.
6

7
FIGURE 3: Recommended Setup of the Diver ComRope
4.2.3. Locate the Hi-USE®connector on the ComRope, and connect it to the Hi-
USE®connector on the EMA-2 (Fig. 2, #19 & 20). Ensure the Hi-USE®
connectors are free of debris and lightly lubricated with a high-grade
silicone grease.
4.2.4 Strain-relieve the ComRope in two places on the diver’s end. The rst
point should have some sort of “D-ring” heavily taped or tied about 4 feet
from the Hi-USE® connector. This “D-ring” will be clipped onto the diver’s
harness or buoyancy compensator via a carabiner or some good-quality
quick-disconnector. This connection will help prevent the ComRope from
pulling on the diver’s full-face mask (Figure 3).
4.2.5 The diver should hand-hold the ComRope about 10 feet from the Hi-USE®
connector (Figure 3). The diver will now be secured to his harness or
buoyancy compensator and have a hand-hold during the dive. The diver
should have control of the ComRope throughout the dive. He should feel
what is going on, giving topside directions when slack needs to be taken
up or when more rope needs to be paid out. If the diver lets go of the
hand-hold, the carabiner–D-ring combination will absorb the tension. In
the event the diver must break loose of the ComRope totally (i.e., in an
emergency), the diver should let go of the ComRope hand-hold and unsnap
the device holding the D-ring. The diver then should let topside know what
is going on before he detaches the Hi-USE®connectors. The diver then
should proceed directly to the surface and reestablish communications
(see the notes on page 8).
4.2.6. The tender should ensure the ComRope on his end is also strain-relieved
in some manner. This will prevent the diver or topside tender from pulling
on the connections made on the MK-7 Buddy-Line electronics module.
Carabiner
D-Ring
This End
Towards
Tender
Hand Hold
10 feet from
Connector

4.2.7 After all connections are made, you can test the system. Have the diver(s)
don the full-face mask. The tender will don the headset with boom
microphone. The boom microphone should be positioned 1/4 inch from
the tender’s lips (keep the microphone as dry as possible).
The MK-7 Buddy-Line will power up the moment the headset and boom microphone
are connected. There is no on/off switch. As long as the headset is plugged in, the
MK-7 will be on and drawing power.
The tender controls all volumes. The volume control labeled “Tender” controls the
volume of the tender’s voice to both divers. The individual volume controls labeled
“Divers” control what the tender hears from each diver. The tender should adjust
all volumes a little at a time until everyone can hear well. Rotating any control
clockwise brings the volume up. Counterclockwise rotation brings the volume down.
- NOTE -
1. If the diver is set up properly, the tender’s pulling on the ComRope should
pull on the diver’s hand-hold rst. If the diver does not have the hand-hold,
the strain should go to the belt “D-ring,” not the diver’s full-face mask or
diver’s earphone-microphone assembly.
Ensure the diver is dressed out such that no unnecessary loops can entangle
him.
2. Excessive volume will cause distortion and hinder communications. Adjust
all volumes slowly until everyone hears clearly. A good rule to follow is “Less
volume is better than too much noise.”
- IMPORTANT SAFETY NOTES -
1. The diver should be dressed in such a manner that he can disconnect from
the ComRope and from the earphone-microphone assembly. If it becomes
necessary to make an emergency ascent, if the diver has to break voice
communications, and if line pulls cannot be established, the diver should
surface and establish communications as soon as possible.
2. We do not recommend you rely solely on MK-7 Buddy-Line voice
communications. A back-up safeguard, such as line pulls, should be
established and practiced (Table 1).
- NO POWER! -
If you connect the headset with boom microphone and the MK-7 does not power
up, verify the batteries are fresh (new).
8

9
Table 1: Recommended Line-Pull Signals
Source: U.S. Navy Diving Manual
From Tender to Diver Searching Signals (Without Circling Line)
1 Pull
“Are you all right?” When
diver is descending, one pull
means “Stop.”
7 Pulls “Go on (or off) searching
signals.”
2 Pulls
“Going down.” During
ascent, two pulls mean “You
have come up too far; go
back down until we stop
you.”
1 Pull “Stop and search where you
are.”
3 Pulls “Stand by to come up.” 2 Pulls
“Move directly away from the
tender if given slack; move
toward the tender if strain is
taken on the life line.”
4 Pulls “Come up.” 3 Pulls “Face your umbilical, take a
strain, move right.”
2-1 Pulls “I understand” or “Talk to
me.” 4 Pulls “Face your umbilical, take a strain, move left.”
3-2 Pulls “Ventilate.”
4-3 Pulls “Circulate.”
From Diver to Tender Searching Signals (With Circling Line)
1 Pull
“I am all right.” When
descending, one pull means
“Stop” or “I am on the
bottom.”
7 Pulls Same
2 Pulls “Lower” or “Give me slack.” 1 Pull Same
3 Pulls “Take up my slack.” 2 Pulls” Move away from the weight.”
4 Pulls “Haul me up.” 3 Pulls “Face the weight and go right.”
2-1 Pulls “I understand” or “Talk to
me.” 4 Pulls “Face the weight and go left.”
3-2 Pulls “More air.”
4-3 Pulls “Less air.”
Special Signals from the Diver Emergency Signals from the Diver
1-2-3 Pulls “Send me a square
mark.” 2-2-2 Pulls
“I am fouled and
need the assistance
of another diver.”
5 Pulls “Send me a line.” 3-3-3 Pulls “I am fouled but
can clear myself.”
2-1-2 Pulls “Send me a slate.” 4-4-4 Pulls “Haul me up
immediately.”
All emergency signals should be answered as given except 4-4-4.

SECTION 5
BATTERIES
An SCB-1 eight-cell AA battery pack (Fig. 1, #14, on p. 4) is provided with the MK-7
Buddy-Line and is located in the lower housing (Fig. 1, #16). The SCB-1 battery
pack consists of an assembled SP-8 battery holder, foam spacer, and contact PCB.
Install eight AA alkaline batteries into the SCB-1 battery pack as follows:
1. Locate the latches on the sides of the lower housing (Fig. 1, #15). Pull up on
the latches simultaneously.
2. Separate the upper and lower modules while being careful not to damage the
o-ring or battery pack contacts (Fig. 1, #12 & 13).
3. Remove the SCB-1 eight-cell battery pack (Fig. 1, #14) and install eight fresh,
1.5-volt alkaline AA batteries per the diagram on the SCB-1.
4. Verify that the o-ring (Fig. 1, #12) is in place, lightly lubricated with a high-
grade silicone grease, and free of debris.
5. Align the SCB-1 contacts to the right when looking through front of lower
housing. Insert the SCB-1 battery pack into the lower housing. Carefully mate
the upper and lower housings together. Ensure that nothing is on the o-ring or
mating surface.
6. Connect the latches from the lower housing to the upper strikes. Pull down
the latches simultaneously until fully down. This will spring-load the upper
and lower assemblies.
7. Look all around the MK-7 to verify the upper and lower assemblies appear
evenly attached with no high spots.
10

SECTION 6
TROUBLESHOOTING
Should you encounter a problem with the MK-7 Buddy Line, follow the remedies
suggested in Table 2.
Table 2: Problem, Probable Cause, and Remedy
Problem Possible Cause Remedy
Corrosion
buildup on the
connectors.
Failure to wash and
lubricate connectors
after use in salt water.
Remove salt water residue or corrosion
from the unit by wiping it with a cloth
saturated in warm freshwater (use
detergent if necessary). Periodically
check the connectors to ensure they are
clean and lightly lubricated with a high-
grade silicone grease.
Poor or no
communications.
Batteries are defective
or dead.
Replace alkaline AA batteries with fresh
ones.
Connectors are not
properly connected or
are damaged.
Clean and check all connectors. Replace
damaged ones.
Headset with boom
microphone is not
plugged in.
Connect headset; unit should power up.
Diver(s) cannot hear
topside, but topside can
hear divers.
Check topside microphone and make
sure the tender volume is turned on and
the microphone is about 1/4 inch from
the tender’s lips.
Diver(s) can hear
topside, but topside
cannot hear the divers.
Check all connections. Check the diver’s
microphone. Verify the diver’s volume
controls are turned up.
Tender and divers hear
light music over the
intercom.
This happens if you are using an
unshielded umbilical and are close to
a transmitting station. The only way
to solve this problem is to change to a
shielded ComRope.
A strong but
distorted signal
is received.
You are speaking
too loudly into the
microphone.
Speak with more moderate volume,
slowly and distinctly.
Your volume controls
are set at too high a
level.
Slowly adjust your volumes as to not
overdrive the system.
11

12
SECTION 7
MAINTENANCE
The MK-7 Buddy-Line is virtually maintenance free and should give you great
service during the life of the unit. The following are recommended service tasks:
1. Try to keep the headset with boom microphone as dry as possible.
2. Do not store the ComRope in a sealed container without drying it rst. It will
grow mold if not dry.
3. If the ComRope was used in salt water, soak it in freshwater for about ve
minutes before drying.
4. If salt water gets onto the headset and/or MK-7, wipe it with a clean cloth and
freshwater. Warm water and a mild soap solution can be used. Wipe it off with
freshwater before drying.
5. Disconnect all connectors when storing.
6. Lightly lubricate the Hi-USE® connector with a high-grade silicone grease.
7. If the MK-7 is not going to be used for a long period of time, the batteries
should be removed.
- PLEASE NOTE -
Although the MK-7 Buddy-Line is a ruggedly constructed piece of your diving
gear, it should be treated like an electronic piece of equipment!
! ! ! CAUTION ! ! !
Use any standard safe entry into the water, but be aware of the additional
equipment you are wearing. Because the ComRope can snag on things, be aware
of obstacles in the area and avoid them. Make sure there is nothing in the water
the diver may hit upon entry.

SECTION 8
HELPFUL HINTS
1. All training should be conducted in a controlled environment such as a
swimming pool.
2. All personnel who intend to use this system should read and fully understand
this manual and equipment before they use it.
3. Divers should be dressed in such a manner that they can disconnect quickly
from the ComRope and/or earphone-microphone assembly.
4. The ComRope should be strain-relieved at both the diver’s and tender’s ends.
It is extremely important the divers have the ComRope strain-relieved to their
harness or buoyancy compensator and not to the full-face mask.
5. The topside tender is in control of the rope topside, ensuring that it is not
getting tangled and that it is not a safety hazard for those walking about.
6. The divers should be aware of their surroundings, making sure their
ComRopes do not become entangled.
7. When a diver must enter the water by jumping into the water, the following is
the recommended procedure: The diver should step up to the end of the pier
or edge from which he is about to jump. The ComRope will be connected to
the diver, who will have a hand-hold on the ComRope. The tender should
lower enough slack so as to just touch the water. The diver looking out
toward the horizon will start his giant step. As the diver steps off, he turns
to face the tender holding on to the ComRope. When he enters the water,
he should be looking at the tender.
- SAFETY NOTE -
If the diver plans to make a jump, it is extremely important the tender does not
forget to pull slack in the ComRope. The ComRope should barely touch the
water while still being attached to the diver. This gives the diver the amount
of rope necessary to hit the water with some slack. If there is no slack in the
rope, the diver could be seriously hurt by being hung or jarred.
13

Undersea Systems International, Inc.,
dba
Ocean Technology Systems
LIMITED WARRANTY
The Aquacom®MK-7 Buddy-Line is fully warranted against
defects in materials and workmanship for a period of one year
from the time of purchase. Our obligation under this warranty
is limited to the replacement of any part or parts that prove
to our satisfaction to have been defective and that have not
been misused or carelessly handled. Labor is warranted for
one year from time of purchase. The complete unit and/or
part must be returned to our factory, transportation charges
prepaid.
We reserve the right to decline responsibility where repairs
have been made or attempted by other than an Ocean
Technology Systems factory-trained service center or properly
trained personnel. In no event shall Ocean Technology
Systems be liable for consequential damages.
Undersea Systems International, Inc.,
dba
Ocean Technology Systems
3133 W. Harvard St., Santa Ana, CA 92704, USA
Telephone [phone] • Toll-Free [phone] • Fax [phone]
E-mail: [email protected]
World Wide Web: http://www.otscomm.com
14
You can now register your product online at the OTS Web site. Just visit http://
www.otscomm.com/register1.html.
© Copyright 2014 by Undersea Systems International, Inc. dba
Ocean Technology Systems. All rights reserved.