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Radio Broadcast Technical Consulting and Sales
10032 Island Drive, Brainerd, MN  56401
E-mail teki@mwpersons.com

MAX-ZII Remote Broadcast Telephone

Note: These units are sold out.  No more production is planned.  We repair existing units to factory specifications. 

In a nutshell:  The Max-ZII is a telephone, similar to what you might have at home.  Plug it into an ordinary dial-up phone line.  Push the line button and you will hear a dial tone.  Use the dial pad on the front of the Max-ZII to dial the call.  There are two audio inputs for microphones or other audio devices and there are two headset outputs so you can hear your audio and audio from the other end of the phone line, just as you would on a regular telephone.  The difference is the convenience and quality of a microphone mixer and headset amplifier.  The unit is not an ISDN or other digital type device.   

The Max-ZII is an industry favorite for remote broadcasting of sporting events via standard telephone lines.  It was designed by broadcasters for broadcasters.  This is a rugged and dependable unit.  Zercom Max-ZII

Wiring for the two microphone/line input connectors:  The Max-Z input is unbalanced.  Use a Switchcraft A3M or equivalent connector.  Pin 1 is shield.  Pin 2 is source -, and is also shield/ground.  Pin 3 is the + input.  Each input is gain adjustable on the rear of the Max-Z from -50 dBm microphone level to +24 dBm line level. One of those channels can have an aux input such as cassette and a microphone input simultaneously.   Both are adjusted by the same front panel control.   

Outputs:  The unit has an RJ11 dial-up telephone line connection.  This is the same as a telephone you might use at home.  The headset amplifier has plenty of output for noisy locations.  Comes with a rechargeable battery that will power the Max-ZII for 10 hours before it needs recharging.  

Zercom Max-ZII rear panel 9 pin Accessory connector pin-outs:
Pin 1 = -6VDC output.
Pin 2 = Audio to Program Amplifier of the Max-ZII.
Pin 3 = Ground. (audio common)
Pin 4 = Program and telephone audio send to the headset amplifier. 
            This feed has the program level reduced to roughly equal telephone audio. 
Pin 5 = Program and telephone audio. 
Pin 6 = Buffered audio from the mixer controls. 
            This pin needs to have a jumper to Pin 2 to make the Max-ZII work properly. 
Pin 7 = no connection. (user definable)
Pin 8 = +6VDC output.
Pin 9 = Ground. (audio common)

Wiring for the two microphone/line input connectors:  The Max-ZII input is unbalanced.  Use a Switchcraft A3M or equivalent connector.  Pin 1 is shield.  Pin 2 is source -, and is also shield/ground.  Pin 3 is the + input.  Each input is gain adjustable on the rear of the Max-Z from -50 dBm microphone level to +24 dBm line level.  The input impedance is 4.7 K ohms and works well with 150 ohm microphones to 600 ohm lines.  

Wiring for the two headset connectors:  There are four 1/4 inch diameter three circuit headset jacks connected to a single low impedance headset amplifier.  Any headset, 4 ohms and up, can be used with the Max-ZII.  There are isolating resistors on each headset jack so that a shorted headset will not prevent audio from being heard on the remaining headset jack.  The jacks are wired "monaural" with tip and sleeve connections.  There is no connection to the headset jack "ring."  If you are using a stereo headset, audio will be heard in only one ear.  To use a stereo headset with the Max-ZII, wire both earpiece wires to the tip connection of the headset plug or build an adapter with a 1/4 inch monaural plug wired to connect the tip to the tip and ring on a 1/4 inch stereo jack.

Size:  The Max-ZII is 8" wide, 3-3/4" high, and 9-1/2" deep.  

Max-ZII Switch

Customers sometimes ask for a switch on Channel 2 of the Max-ZII.  This 3-position selector allows the Channel 2 control to handle Microphone-only, Tape-only, or Microphone and Tape simultaneously.  

We charge $50.00 for installation of this option.  

Max-ZII Rear Panel

Customers often need a record output.  We add these 1/8" (3.5 mm) jacks to the rear of the Max-ZII for $50.00.  Be sure to specify line level (-4 dBm) or microphone level (-50 dBm)  

To get your choice of line level (-4 dBm) or microphone level (-50 dBm) simultaneously, we can install two 1/8" (3.5 mm) stereo audio jacks on the left rear panel for $60.00
.  You can use a stereo or or monaural cable to feed audio to a stereo or monaural device such as a recorder or computer.  When a stereo (3-circuit) cable is used, the same Max-ZII monaural audio is fed to left and right channels.  When a monaural (2-circuit) cable is used, no special rewiring is required.  Monaural is fed to the recorder or computer.

Older units use an IEC power cord, which are identical to computer power cords.  Those Max-ZII units have an internal power transformer.  This can cause some hum in the audio.  To remedy the hum, the later Max-ZII units were fitted with an external power supply.  This requires changing the rear panel power connector to a round DIN receptacle.  You can see the connector in an aluminum filler-plate on this rear photo.  We charge $60 to make the modification.  That includes the $30 external power supply.    

Non-warranty repairs:  Click here

Frequently requested repair parts that we stock: Price Each
External wall-mounted power supply with 5-pin DIN plug (used on later production units) Model number A482400400U.  (best to buy two so you have a spare on hand when you loose one.)  There is a $2.00 discount on each power supply when buying two or more.  Details $22.00
A5K Front panel audio level controls for channel inputs $8.88
Instruction manual with schematic diagrams.  Specify for unit with regular power cord or unit with wall power supply. $25.00
Rechargeable battery. (requires disassembling the unit to install) $29.80
120 VAC IEC power cord (used on earlier production units) (same as power cords on most computers) $6.00
Rear panel input channel audio gain controls. $5.82
Rear panel headset jacks $12.00
Rear panel level knobs. $3.00
Front audio gain knobs with pointer-skirt and cap. $3.98
Front headset gain control knob $3.26
Front headphone slide volume control.  $12.00
Piezo buzzer. $17.00
Signetics NE5533N IC's (It is normal for the audio to have hiss when the back-panel audio gain is turned all the way up.  Just turn it down 1/8 turn.  This does not indicate a bad IC.) $25.00
HM9113A Dialer Integrated Circuit


Front panel push-on, push-off switch without light.  Used for tone/pulse. $18.58
Front panel push-on, push-off switch with red light.  Used for line, cut 2, and power. $26.80
Telephone line transformer T1 $21.82
Telephone cable, 14 feet long. $2.00
Carrying Cases:  We do not have any cases for the Max-ZII, but we do have soft/padded cases for the Zercom Max-Z.  These are larger (18" x 14" x 5") and have room for a Max-ZII along with microphone/headsets and other gear.  The case has a handle and shoulder carrying strap.  New. $49.00
Additional parts available upon request e-mail

INQUIRIES:  The best way to get answers to your questions is to e-mail teki@mwpersons.com.  If we are in the office, you will have a reply within an hour.  If we are not in the office, you will have to wait.

SHIPPING:  We normally ship via United Parcel Service.  We DO NOT SHIP INTERNATIONALLY.  If you are an international buyer and have a shipping broker in the United States, we will be glad to ship to them.  We do not ship packages outside of the 50 United States. 

ORDERS:  E-mail your order with a complete street address and telephone number.  We will e-mail you an invoice for the total amount including shipping based on size, weight, and destination.  

PAYMENT:  We now handle VISA credit cardsSend us your credit card information along with your order.  If you would rather not send the credit card data in an e-mail, then give us your telephone number and we will call you to get the number.  You can also pre-pay by cashier's check or money order. 

M. W. Persons and Associates, Inc.
10032 Island Drive
Brainerd, MN  56401

Non-warranty repairs:  Click here

Tech Tips from our Knowledge Base: 
If the Touchtone dialer does not seem reliable, the battery voltage might be below 9 VDC.  The normal battery voltage is 12 VDC.  As battery voltage drops, Touchtone audio drops in level and becomes distorted.    
A good battery will run the unit for 8 hours on a full charge.  When the power cord is plugged into 120 VAC power, the battery will charge regardless of whether the unit is turned on or off.  It takes 24 hours to recharge a dead battery.
On most units, there can be excessive noise in an input channel if the input gain control, at the rear of the unit, is turned to maximum.  Back it off 1/8 of a turn and the noise will go away.
For analog cellular to Zercom Max-Z or Max-ZII, use a "data jack" or "fax Jack." These items are provided by and installed on a cell phone by the people who sell cellular telephones. For Motorola cellular phones, Motorola suggests the " S1936C Cellular Connection Data Jack." The jack provides the equivalent of regular telephone service like fax, computer modem, answering machine, etc. The Zercom unit plugs into the jack on the side of the telephone using it's standard modular telephone cable. The S1936C even accepts rotary dial pulses. This could cost $250 installed.  We do not do that work here. 
To connect a Max-ZII to a digital cellular telephone, you can use a JK Audio Daptor One.  It converts the 2.5mm headset jack on a wireless cellular phone to a modular RJ-11 jack, the same as a regular telephone line.
To connect a Max-ZII to cellular telephone service, you might use a Verizon Wireless Home Phone Connect device.  It is a box that looks like a wireless router, but it talks directly to a nearby cell tower and provides a standard RJ-11 telephone jack for plugging an ordinary telephone in or a Zercom Max-Z Remote Broadcast Telephone.  In essence, it is like having a wired telephone line, but it is portable to anywhere.  Just plug it in and you have a telephone line.  Great for sports broadcasts or remote broadcasts of any kind.    Other cell phone providers probably have a similar device.  This is probably your BEST choice.
Headset Wiring:  The headset jacks on the rear of the Max-XII are standard 1/4 inch.  They are monaural which means audio comes out the "tip", but not the "ring" connection. If you plug a stereo headset into the Max-ZII, you will hear audio in just the left ear.  If you want audio in both ears, you need to short the tip and ring connections inside the headset connector or make an adapter to do that.  We can make a 6 inch adapter cable with a monaural plug at one end and a stereo jack on the other end for $20 plus shipping.  As an alternative, we can remove the two stereo headset jacks in the Max-ZII and replace them with stereo jacks for $50.  Add shipping.  That work is done here in the shop and not easily done in the field.
Microphone (Audio Input) Wiring:  The audio inputs are standard A3F jacks.  They are not balanced, but instead have Pin 2 tied to ground, which is the same as Pin 1, which is the shield.  That means the "hot" side of the audio must go to Pin 3.  This configuration is the same as Marti remote pickup transmitters, but is different than the International standard where Pin 2 is the audio input.  If the microphone or other audio source you have is unbalanced and outputs its audio on Pin 2, then you will need to change the connector wiring on that source cable or make an adapter where Pins 2 and 3 are transposed.  We can build and sell you a 6 inch adapter cable to do this for $20.00 plus shipping.   
Hum in Headsets:  Some customers report they would like to reduce the hum that is heard in their headsets.  This hum is heard when the unit is plugged into 120 VAC power.  The hum is hardly heard in the programming that runs through the unit.  To dramatically reduce the hum, we have an upgraded version of the external wall-mounted power transformer.  The transformers are $30.00 plus shipping and tax.  The change may require swapping two wires inside the Max-ZII unit to get the "power" light to come on.  If your unit has a standard computer-type power cord, then the unit will need to be modified to accept an external power supply.  The modification, in our shop, runs $90.00 plus shipping. A new $30.00 power supply is included in the $90.00 price.
Line Level Output:  You can get -10 dBM balanced audio output from the Max-ZII from the Dial Up telephone line jack.  It is a type RJ-11.  The two center conductors are + and - audio. 

Unsolicited Comments:

July 15, 2015
You may enjoy knowing that this unit was used in the emergency broadcast location for KWMR Radio, Point Reyes Station, California, a community radio station on the coast, north of San Francisco.  It is an area that often sees floods, fires, and earthquakes.  In fact, we sit astride the San Andreas fault.  Our emergency location is on the Pacific Tectonic Plate while the station is on the North American Plate!  The Max-ZII has been the ideal unit for our purposes so I appreciate the the fact that it is such a good unit and that you continue to support it.  Best Regards,  Richard Dillman, KWMR Radio

February 1, 2009: 
I bought a Max-Z around 1989, and absolutely loved it.  If the unit were a car, I would have "driven" it the equivalent of about 300,000 miles.  Minor league sports can be incredibly tough on equipment, and both the Max and the Max-ZII have been outstanding.   Used the Max-ZII for an entire hockey season a year or so ago, and that's brutal stuff, with set up and tear down before and after every game.  Despite needing repair, I've had the units now for 10 years, most of that time doing two sports (70 or so hockey games and 140 baseball games per year).  It's been remarkably good.  Thanks again!  Bob in Oakland California

   Email Mark Persons:  teki@mwpersons.com    

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page last edited 12/21/2016