JK Audio JK-INTCHG Interchange LTD Intercom Phone Bridge + Digital Hybrid User Guide

Interchange LTD™
Intercom Phone Bridge + Digital Hybrid
User Guide

Welcome
Thank You
Thank you for purchasing a JK Audio Interchange LTD™ Intercom Phone Bridge.
Please read this guide for instructions on setting up and using your new product.
Getting Assistance
If you have technical or application questions, call us M-F: 8:30 am-5:00 pm (CT)
In the US & Canada (Toll-Free)
All other countries:
800-552-8346
815-786-2929
Email us at: support@jkaudio.com
Or check out our FAQ section for answers to common questions.

Warnings & Safety Precautions

• Read and keep these instructions.
• Follow all instructions.
• Clean only with a soft dry cloth.
• Refer all servicing to qualified service personnel.
• Heed all warnings.

Warning: Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
Warning: Do not defeat the safety purpose of the three-prong grounding- type plug. If the provided plug does not fit into your outlet, consult an electrician for the replacement of the obsolete outlet.
Warning: Do not use this unit if the electrical power cord is frayed or broken. The power cord should be routed so that it is not likely to be walked on or pinched by items placed upon or against it.
To reduce the risk of fire: Use only No. 26 AWG or a larger telecommunication line cord.
To reduce the risk of fire or electric shock: Do not expose this apparatus to rain or moisture.

Limited Warranty
The Interchange LTD is covered by a 1-year warranty to be free from defective workmanship and materials. To obtain service, contact JK Audio by phone or email for return authorization. Once authorized, you will carefully pack and ship the faulty product and all accessories to us. You will pay for shipping to us and we will pay for the return back to you.
This warranty does not cover damages due to accident, weather, fire, flood, earthquake, misuse, unauthorized repairs or modifications, or damages that occurred in shipping, only defective workmanship or materials.
There are no expressed or implied warranties that extend beyond the warranty here made.

Features

Male and Female 3 Pin XLR Intercom Loop Jacks| Front Panel TRRS Monitor Headset Jack with Volume Control
---|---
Male XLR Mix Line Out for Monitoring| Listen Always, Talk When Talk-Enabled
Send and Receive LED Metering| Enable/Disable Auto-Answer
Front Panel Screwdriver Level Controls| 16-bit DSP Technology
Front Panel Channel Select| Front Panel Off-Hook LED
Front Panel Cell Phone Interface| Send and Caller Signal Level LEDs

What’s in the Box?

• Universal Power Supply with Detachable Cord
• 3.5 mm TRRS Headset Interface Cable (Part# CN113)
• RJ11 Phone Cord

Introducing the Interchange LTD™
Interchange LTD allows remote access to your party-line intercom system.
This 1RU rackmount interface includes a digital hybrid for connection to analog (POTS) phone lines. The front panel headset interface jack allows easy connection to your wireless phone, tablet, or computer allowing remote access through a phone call or conferencing app. The front panel DTMF keypad and headset jack allow easy call setup.
The Listen-Always design allows both the phone hybrid and the mobile phone headset interface to monitor the intercom just like any other belt pack. Listen mode is a high impedance bridging tap on the intercom line. Talk mode is enabled via a front panel switch, either Off, On, or Auto. Auto follows the phone’s hybrid Auto-Answer mode.
The internal digital hybrid connects intercom audio to a standard analog telephone line without the transmit/receive crosstalk common to analog hybrids.
Its DSP continuously monitors both the phone line and audio signals to deliver excellent separation. This proprietary, dual-convergence echo canceller algorithm can achieve excellent separation, typically exceeding 50 dB, without any setup and without sending a noise burst down the line.
Ready to go?
The Interchange LTD controls and connectors are clearly marked and ready for operation. If this is your first exposure to a hybrid, we suggest that you read the entire manual to allow you to take advantage of all these features.
Any Questions?
Before you pick up the phone… Please thumb through the rest of this manual.
You might find those deep technical questions are covered in later pages.

Getting to Know Your Interchange LTD

Controls & Indicators

1. Talk Control
   The position of the three-position toggle switch determines when Interchange LTD will send audio into the Party Line intercom.
   Up = Talk: Interchange LTD sends and receives audio (simultaneously).
   Use this position with the headset interface.
   Center = Off: Interchange LTD functions as a listen-only device. No audio will be sent into the Party Line intercom.
   Down = Auto: The talk function follows the hook state of the innkeeper Phone Hybrid.

2. Intercom Channel
   Up = Audio on Intercom Channel 1/A (Pin 2)
   Down = Audio on Intercom Channel 2/B (Pin 3)

3. Talk LED
   Indicates audio transmission into the Party Line intercom.

4. Intercom Power LED
   Indicates intercom power detected.

5. COM Level LEDs
   Indicates audio signal level from the Intercom channel. The 0dB LED corresponds to a nominal level of -10 dBu on the intercom channel.

6. Phone Level LEDs
   Indicates audio signal level from the phone interface.

7. Com Balance
   Fine-tuning for the intercom hybrid function. Optimizes separation between send and receive when pushing audio into the intercom with the Talk function.
   Controls Cont’d

8. Headset Interface Send Level
   Adjusts audio signal level to the mobile device.

9. Headset Interface Receive Level
   Adjusts audio signal level coming from the mobile device.

10. Headset Interface Jack
    Connect to the headset jack of your mobile device with supplied CN113 interface cable if no phone line is available.

11. Auto-Answer
    When enabled, Interchange LTD automatically answers an incoming call and then disconnects after the caller hangs up. The auto-answer will occur on the first ring.

12. Numeric Keypad
    Dial a number.

13. Redial
    Press this button to instantly redial the last telephone number.

14. Call Button
    Takes the line off-hook; press this button to answer a call or you can direct a call from your aux phone through the hybrid.

15. OH LED
    Lit when you are online with a call (off-hook).

16. Power LED
    Lit when the unit is plugged in and receiving power.

17. Drop Button
    Press this button to drop (hang up) a call.

18. Signal LEDs
    Send LEDs to represent the signal level going out to the telephone line.
    Caller LEDs represent the signal level coming from the phone line, after the DSP.

19. Send and Receive Level
    Adjusts the audio signal that you are sending down the telephone line and the level of the incoming caller’s audio as it is going out the Mixout jack.

20. 3.5mm TRRS Headset Jack with Volume Control
    Monitor Intercom/Hybrid audio with a TRRS headset.

Getting to Know Your Interchange LTD

Inputs & Outputs

1. Phone Line
   Connect to a standard, single line, analog telephone line.

2. Aux Phone
   Connect a single-line analog telephone for call setup/dialing, or producer call screening.

3. Power Jack
   For connection only to the supplied 9VDC regulated power supply.
   AC power to Interchange LTD is only necessary when interfacing a POTS line to your intercom system

4. Party Line Intercom
   Connect to one or two-channel 3-pin unbalanced Party Line intercom system.

5. Mix Out XLR Jack
   Contains a line-level mix of both the phone and intercom audio.

Getting Connected

Start by Connecting to the Intercom

1. Set the < Talk> switch to the < Off> position, and the < Com> switch to the desired channel.
2. Connect Interchange LTD to your intercom network using one or both of the  < Intercom> XLR jacks.
3. As soon as Interchange LTD is connected to the intercom system, the < Power> LED will light, and the < Com> LEDs will indicate any audio signal present on the intercom channel.

If using a Mobile Device (If using a phone line, please skip to page 6.)

Note: AC power is not necessary when used with a mobile device.

1. Connect the supplied CN113 interface cable between the front panel Headset Interface jack and your mobile phone headset jack.
2. Using your mobile phone, place a call to a remote location. You should be able to immediately monitor the intercom signal from the remote location.
3. Adjust the < Headset Interface Send> level control for the desired signal level at the remote location.
4. Change the < Talk> toggle switch to the < Talk> position to allow the remote location to be heard on the intercom channel.
5. The return audio path from the remote location into the intercom can be adjusted in two ways. The front panel < Headset Interface Receive> level control provides adjustments suitable for most mobile devices. However, most mobile devices also have a headphone level control which works along with the Interchange controls.
6. It is best to set the headphone level on your mobile device first, then set the level on Interchange for final adjustment. This signal will appear on the Interchange < Phone> LEDs, not necessarily on the < Com> LEDs. Monitor receive levels by listening on an intercom belt pack.

Com Balance with Headset Interface
Interchange LTD features an active hybrid to separate the unbalanced 2-wire intercom audio channel into separate (4-wire) send and receive audio paths.
While nominal separation is achieved with a typical operation, the separation can be fine-tuned if the intercom loop offers additional challenges. Perform the tuning operation when the intercom network is not in use. Using your mobile device, play or generate a fixed level tone or white noise into the intercom system. Adjust the signal level to 0 dB on the Interchange < Phone> LED display. Be sure that the < Talk> control switch is in the < Talk> position. Adjust the < Com Balance> control while observing the < Com> LEDs, to find the minimum (the position where the fewest < Com> LEDs are lit). Remove the test signal and proceed with normal operation.

Operation

Operation with a Phone Line

1. Connect the supplied RJ-11 phone line cable between the jack marked < Line> and your wall jack. Be sure this jack supports standard single-line analog telephone operation.

2. Connect the supplied AC power cord to the back of the Interchange LTD and then to an AC power outlet.
   This device should be connected to an adequate surge protective device at all times both for the power connector and for the telephone line to avoid damage from lightning or electrical surges.

3. Your Interchange LTD is now ready to take calls. Along with using the front panel keypad, you may also connect an auxiliary telephone to the Interchange LTD < Phone> jack so you can dial out and set up calls, or use the < Auto-Answer> feature to answer incoming calls.

4. Change the < Talk> toggle switch to the < Auto> position to allow Interchange LTD to follow the call status of the phone hybrid. During an active call, the remote location can now be heard on the intercom channel.

5. The signal from the remote location will appear on the Interchange LTD < Phone> LEDs, not necessarily on the < Com> LEDs. Monitor receive levels by listening on an intercom belt pack or TRRS Headset.

6. Changing the < Talk> switch to < Off> returns the system to a remote Listen-Only configuration.

Com Balance with Phone Hybrids
Interchange LTD features an active hybrid to separate the unbalanced 2-wire intercom audio channel into separate (4-wire) send and receive audio paths.
While nominal separation is achieved with a typical operation, the separation can be fine-tuned if the intercom loop offers additional challenges. Perform the tuning operation when the intercom network is not in use. Interchange LTD does not have a test tone feature, therefore an alternate tone generator must be used.
Be sure that the < Talk> control switch is in the < Talk> position. Adjust the < Com Balance> control while observing the < Com> LEDs, to find the minimum (the position where the fewest < Com> LEDs are lit). Remove the test signal and proceed with normal operation.

Auxiliary Telephone
An auxiliary telephone provides you with an easy way to dial out or set up your calls. Interchange LTD will disconnect the auxiliary telephone when you press the < Call> button. If you need to take the call back on the aux telephone, simply pick up the telephone handset before the Interchange LTD’s < Drop> button is pressed.
To use an auxiliary phone equipped with a “Hold” feature to place or screen a call, first set up the call and place the call on hold. When you are ready to take the call on Interchange LTD, press the < Call> button on the innkeeper LTD and your telephone will automatically release the hold.
Your phone will operate as a normal telephone anytime you are in Drop mode.
Leaving the hybrid connected between the wall jack and your telephone will not affect the normal use of your phone. Audio will only pass through the hybrid when you press the < Call> button.

Optional Jumper Settings
If the incoming Caller level is too high and peaking the red -3 dB LED, you may need to change the setting of an internal jumper. Disconnect power from the hybrid and remove the cover of the innkeeper LTD to locate Jumper 1. The default position for this jumper is closed (covering both pins). Changing the jumper to the open position (either remove the jumper or cover just one pin) will provide 6 dB attenuation of the incoming audio signal.

Auto-Answer
The feature will answer on the first ring.
When is enabled, you can still make calls manually using the