with reference to fig1 , a catheter - based electroanatomical navigation system 10 is shown for use with a catheter 40 , an extension cable 41 and a dongle 42 , in accordance with the present invention . the system 10 includes at least one monitor 12 , a patient interface unit ( piu ) 14 , a location pad 16 , a signal processing unit 20 , an ablation energy generator 22 , a workstation 24 and a printer 26 . the monitor 12 displays patient data and maps . the piu 14 allows cable connections between the signal processing unit 20 and all other system components . the location pad 16 is for placement under a patient lying on a patient table 18 , enabling accurate detection of catheter location . the signal processing unit 20 determines all location and performs ecg calculations . the generator 22 may be an rf generator for supplying rf energy to the catheter . the workstation 24 is a computer adapted for storing patient data and maps . the printer 26 is provided to print color maps produced by the system 10 . as shown in fig1 and 2 , the dongle 42 extends between piu 14 and the catheter 40 , providing an electrical connection and performing any function ( s ) used or necessary for data gathered and transmitted by the catheter to be understood and processed by the system 10 . accordingly , the piu 14 includes at least one electrical connection interface , for example , port 30 configured to interface with the catheter 40 via the dongle 42 . in one embodiment , the catheter 40 has an elongated catheter body 112 , a distal section 114 carrying tip and / or ring electrodes 117 and a control handle 116 . as shown in fig3 , lead wires 140 are connected to the electrodes 117 for receiving and transmitting electronic signals for generating patient data , including 3 - d anatomical maps of the patient &# 39 ; s heart and ecg readings which are displayed on the monitor 14 and stored in the workstation 24 . moreover , electromagnetic position sensor ( s ) carried in the distal section 114 are responsive to external magnetic fields generated by the location pad 16 below the patient table 18 for generating electrical signals representative of the location of the distal tip section . sensor cables 132 are connected from the position sensors to transmit these signals . both the lead wires 140 and the sensor cables 132 extend through the length of the catheter , passing through the distal tip section 114 , the catheter body 112 and the control handle 116 . in that regard , a proximal end 116 p of the control handle has at least one electrical connection port 30 to enable electrical connection with the lead wires 140 and sensor cables 132 . in one embodiment , the extension cable 41 between the catheter 40 and the dongle 42 has a proximal end 41 p and a distal end 41 d , as shown in fig2 . the distal end 41 d is provided with a first interface , for example , plug 43 configured to be received in the electrical connection port 30 at the proximal end 116 p of the control handle . the proximal end 41 p is provided with a second interface , for example , plug 44 configured to be received in an electrical interface , for example , port 45 provided in a distal end of the dongle 42 . in one embodiment , the dongle 42 has a proximal support portion including a semi - rigid dongle cable 53 , and an elongated distal body or housing 54 with a proximal end 54 p , a distal end 54 d and a generally sealed interior cavity extending therebetween , as shown in fig4 . at the distal end 54 d , the electrical port 45 is configured to receive the second interface plug 44 of the extension cable 41 . at a proximal end of the cable 53 , an electrical interface , for example , plug 55 is configured to be received in the electrical port 30 of the piu 14 . in the illustrated embodiment of fig4 , the dongle 42 houses hardware , for example , at least one printed circuit board ( pcb ) 60 which receives the electrical signals representative of catheter location transmitted by the sensor cables 136 to through the extension cable . the pcb 60 may amplify the signals and convert to a form readable by the signal processing unit 20 of the system 10 which are then transmitted via the proximal dongle cable 53 . with reference to fig5 and 6 , the proximal cable 53 has an elongated flexible outer tubing member 62 defining a lumen 63 through which dongle wires 64 extend between the proximal and distal ends of the cable . in accordance with a feature of the present invention , the cable 53 is semi - rigid with shape memory so that the cable can be manipulated and configured by a user to selectively position or orient the dongle body 54 as desired . in one embodiment , the outer tubing member 62 comprises spirally wound flat strip ( s ) 67 of metal , metal alloy or generally rigid plastic material with longitudinal folds 69 , interlocking adjacent longitudinal side edges 71 to form what is commonly referred to as a “ gooseneck ” tubular structure with a corrugated - like profile which provides flexibility and shape memory such that it can be manipulated into and retain a variety of desired configurations . the tubular structure may also act as a strain relief and / or a trunk cable insulation covering . the wires 64 extending through the tubing member 62 are protected and sealed within the tubing member 62 . fig6 illustrates another embodiment of a flexible cable or gooseneck tubular structure comprising an inner coiled spring 80 and an outer sectional wire 82 wrapped around the coiled spring 80 . in the illustrated embodiment , the underlying wire of the spring 80 has a circular cross - section and the outer sectional wire 82 has a triangular cross - section , wherein the underlying wire of the spring 80 is nested between two inner vertices v of adjacent pairs of sectional wires 82 . in use , the dongle 42 is connected to the piu 14 via the connector plug 55 being received in the connector port 30 , as shown in fig2 . a distal end of the dongle 42 receives the proximal connector 44 of the extension cable 41 . the distal connector 43 of the extension cable 41 is received in the connector port 30 of the control handle 116 . in a diagnostic procedure , as electrical signals are sensed by the tip and ring electrodes 117 on the distal tip section 114 of the catheter 40 positioned in patient &# 39 ; s heart 125 , the signals are transmitted via the lead wires 114 through the distal tip section 114 , the catheter body 112 and the control handle 116 . the signals are transmitted from the control handle 116 to the piu 14 for processing by the signal processing unit 20 by the extension cable 41 and the dongle 42 . in a therapeutic procedure , rf energy from the rf generator 22 of the system 10 is delivered to the tip and ring electrodes 117 via the piu 14 , the dongle 42 , the extension cable , and the lead wires 140 extending through the control handle 116 , the catheter body 112 and the distal tip section 114 . for position sensing of the catheter distal tip section 114 in the heart 125 , electrical signals from the position sensors carried in the catheter distal tip section are transmitted via the sensor cables 132 which extends from the distal tip section , to the catheter body 12 , and the control handle 116 . the signals are further transmitted via the extension cable 41 to the dongle 42 which provides the pcb 60 that may amplify and / or convert the signals before transmitting them to the piu 14 for processing by the signal processing unit 20 of the system 20 . accordingly , the dongle of the present invention renders a catheter more disposable and “ greener ” by allowing expensive and metal - bearing hardware to be relocated from the catheter and onto the dongle . moreover , the semi - rigid dongle of the present invention reduces the risk of damage to the dongle , the catheter and the navigation system by allowing the user more selection in the placement and positioning of the dongle . in an alternate embodiment as shown in fig7 , a dongle 42 ′ is illustrated with a proximal support portion including a semi - rigid dongle arm 66 whose proximal end carries the electrical plug 55 . the arm 66 comprises a tightly coiled spring whose diameter may vary or be uniform throughout the length of the arm . the wires 64 extending through the spring are protected by the spring . the spring may be manufactured with different degrees of stiffness depending on the use and application , and be provided with a preformed shape . in the disclosed embodiment , the spring has sufficient stiffness to support the dongle body in a horizontal position but allows elastic bending or displacement where the dongle body is accidentally bumped . it is understood by one of ordinary skill in the art that the body of the dongle may house a variety of electrical hardware for receiving and processing ( including , for example , amplifying , converting , digitizing , etc .) a variety of electrical signals ( including , for example , optical , audio , etc .) between the catheter and the navigation system , as needed or appropriate . the preceding description has been presented with reference to presently preferred embodiments of the invention . workers skilled in the art and technology to which this invention pertains will appreciate that alterations and changes in the described structure may be practiced without meaningfully departing from the principal , spirit and scope of this invention . in that regard , the drawings are not necessarily to scale . accordingly , the foregoing description should not be read as pertaining only to the precise structures described and illustrated in the accompanying drawings , but rather should be read consistent with and as support to the following claims which are to have their fullest and fair scope .