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Clear-Com EF-701M


The EF-701M interface converts a single channel of standard or TW partyline intercom to four-wire audio, while also converting call signals to RS-422 data (and back). The resulting four-wire audio plus RS-422 data can then be sent to a Clear-Com Matrix port, fiber-optic converter (modem) or connected to another EF-701M over twisted-pair cable such as CAT-5E. 

When used with a Matrix system, the EF-701M allows a party-line channel to be connected to the frame with up to 5000' of cable. With its excellent hybrid null and wide-range level controls the unit may also be used as a best-quality stand-alone two-to-four-wire converter.

For travelling systems that require long connecting runs between stations or systems, EF-701M's can quickly recover their cost in space and weight savings, as fiber-optic and UTP cables are lighter and more compact than standard shielded mic cable. Two EF-701M's can be connected directly to each other over low-cost four-pair, unshielded, twisted-pair cable (UTP). The EF-701M's low profile and compact size add to its portability. It can easily be mounted on a utility rack shelf and up to three units will fit across in a standard 1-RU rack space. No additional power connection is required, as the EF-701M obtains its DC operating current through the party-line connection on pin 2 of the XLR connector.

For systems where only one or two part-line channels are needed, the EF-701M is ideal. Simply run UTP cable from the Matrix frame to the EF-701M, which is connected to and powered by the party-line system. A rear panel dip-switch on the EF-701M selects connection for the four-wire audio and data as the RJ-45 jack, instead of the DB-15, simplifying set-up.

Call Signaling
In addition to its acting as a visual indicator, call signaling can be used to trigger relays or functions in other intercom equipment. An amber data LED provides the user with continuous status on the data link between two EF-701M's and will indicate whether or not a proper link has been established. The EF-701M also includes internal jumpers to select different baud rates for the RS-422 data.

Nulling Circuitry
The superior hybrid nulling circuitry of the EF-701M allows multiple units to be used together on a single party-line channel. Wide-range controls are provided for audio level adjustments along with three front-panel trim pots for complete hybrid null adjustments.


  • High quality party-line to four-wire audio conversion
  • Maintains hybrid null with multiple units on achannel
  • Converts call signals to RS-422 data with selectable baud rate
  • Connect intercom with call signal over fiber-opticsystems
  • Clear-Com and RTS compatible
  • Built-in test tone and jack for nulling
  • Multi-mode Data status LED
  • Powered by intercom line
  • Connects with standard XLR's and RJ-45 or DB-15
  • Rugged, compact package can fit up to three across on standard 1-RU rackshelf CC/TW


  • Broadcast facilities, theme parks, campuses, sports complexes, large research and test facilities with fiber-optic infrastructure
  • Portable systems requiring long cable runs
  • Extend connection lengths between stations or systemsup to a mile with standard UTP cable
  • Connect a Clear-Com channel to a channel of RTS-TWwith fiber or UTP in between
  • Connect Clear-Com PL or RTS-TW to a Matrix Plus 3frame
  • Utilize existing, installed UTP to connect intercom locations