HAMTRONICS® AP-3 AUTOPATCH MODULE: INSTRUCTION MANUAL and the receiver squelch is closed. preventing transistor damage. C8 is FUNCTIONAL DESCRIPTION. Therefore, the radio station using the a bypass for low frequency rf which The Autopatch Module is used repeater has control over what parts may be present on the telephone line. with the DTMF Decoder/Controller of the incoming telephone DTMF tones from either the phone Module to provide the following conversation goes out over the air: line or the receiver are applied to the functions: repeater autopatch, any time the radio operator keys his DTMF De coder/Controller Module reverse autopatch, primary phone microphone, the receiver squelch through E8. line remote control of repeater, phone cuts off the telephone audio at U1-D. line monitor of repeater receiver, and Logic Circuits. C10 prevents switching clicks from secondary remote control through When the DTMF De - occurring when a dc signal is applied repeater receiver. coder/Controller Board applies a through R12 or R13. The 220 pf The Autopatch Module can be ground signal to E13, two things capacitors at various input and output interfaced directly with any touchtone happen. First, switch Q1 turns on, terminals of the board are to bypass telephone line. It is registered with thereby applying a positive signal to vhf/uhf rf energy. the FCC under part 68. the COR input on the COR Board. Audio from the repeater receiver This turns on the repeater enters at E7. Some of this audio is HOW IT WORKS. transmitter. Second, the ground applied through R16 and mixer U1-C Refer to the schematic diagram signal at E13 is applied to or-gate U1- and E9 to the transmit audio input and the repeater block diagram dur- A, which energizes relay K1 through circuit on the COR board. Because of ing the following discussions. switch U1-B. R32, CR3, and C26 in the squelch action in the receiver, the line to U1-A provide a time delay Phone Line Interface. audio is present only when a station of about one second between the time The phone line is connected to E1- is heard on the receiver. Thus, the DTMF Board commands the E2. Relay K1 completes a path to dc receiver audio does not interfere with autopatch to turn on and the time the load resistors R6/R7 and to isolation audio coming from the telephone line. relay actually energizes. This transformer T1 via high voltage Q5 acts as a switch to mute the prevents the tail end of the last digit capacitor C5. When the phone patch audio at the input of U1-C whenever in the sequence which energizes the relay is activated, the dc current the DTMF Decoder/Controller Board autopatch from being applied to the drawn by R6/R7 "seizes" the phone applies a signal indicating that tones telephone line and thereby being line, and T1 couples audio in and out are being received. This prevents construed by the telephone exchange of the line. When the phone line is tones from being repeated on the as the first digit in the telephone "on-hook", any incoming ac ringing transmitter. Capacitor C15 works in number. voltage is coupled through capa citors conjunction with a diode on the TD-2 The phone patch relay also can be C6 and C99 to opto-coupler U2. When DTMF De coder/Controller Board to activated by timer U3. If someone the opto-coupler senses a ringing provide a fast-attack/slow-release calls in on the phone line, opto- voltage on the line, it trips timer U3. time constant for the mute switch. coupler U2 detects the ringing Receiver audio is applied through Audio Paths. voltage, and U3 activates the relay for potentiometer R1 to line driver Q4, When the autopatch is enabled, about 60 seconds. This is sufficient which amplifies the signal and drives relay K1 connects the telephone line time to give a tone command or listen the telephone line through isolation to isolation transformer T1 through dc to the repeater receiver to hear what transformer T1. Bias for the stage is blocking capacitor C5. Phone line is on the input frequency. During the switched on by Q2 only when the re- audio is amplified in two successive 60 seconds, a tone command may be ceiver squelch is open. Because U1- op-amp stages. The repeat phone line given to turn the repeater or the D is off during this condition, the level is set by potentiometer R8. U1- autopatch on or off or to perform any amplified audio from Q4 is blocked D also acts as a switch: audio passes other function which the DTMF Board from the input of U1-C through this only when the autopatch is enabled is programmed to do. If the autopatch second path. (The high gain needed is turned on, of course, then it stays in U1-D for the weak phone audio on even after the 60 second period would cause distortion of the receiver HOW TO CONTACT US — elapses. audio if allowed to take the same path Hamtronics, Inc. The COR Module keying output at as the phone audio.) 65 Moul Rd; Hilton NY 14468-9535 E12 is activated by Q1 whenever the Phone: 716-392-9430 VR1/VR2 is a pair of back-to-back autopatch is turned on, as previously http://www.hamtronics.com zener diodes to absorb the inductive de scribed. It also is activated by Q2 email: [email protected] surge when Q4 is switched off, thus and Q3 via or-gate CR2 whenever the ©1998 Hamtronics, Inc.; Hilton NY; USA. All rights reserved. Hamtronics is a registered trademark. Revised: 11/27/01 - Page 1 - receiver squelch is open. This is the the new relay. Therefore, the lead of TABLE 1. CONNECTIONS BETWEEN manner in which the COR line is R33 closest to the relay no longer MODULES WHEN AP-3 IS USED WITH COR-4. activated when the autopatch is off, connects directly to the board. See SIGNAL RCVR TD-2 AP-3 COR during basic repeater operation. Q2 the detail to the left of the drawing. Rcvr Audio E2* E7 also switches bias to Q4, and Q3 The leads of C99 are bent so that one AP Audio Out E9 E12 switches bias to mute U1-D, goes down into the board where R33 Rcvr COS E4* E11 AP COR Out E12 E14 whenever the receiver squelch is originally connected. Do not trim the DTMF Rpt Inhibit "H" E16 open. (COS = carrier operated lead off. Instead, bend the C99 lead DTMF Tones "1" E8 switch). under the board and use it as a DTMF Mute "3" E10 jumper to connect to the second pad AP-ON Command "4" E13 CONSTRUCTION. *Note: Inside receiver enclosure, E2 and from the right of the row of five Assembly is fairly simple. Refer to E4 on the receiver module are connected to original relay pads, as shown in the feedthru capacitors C2 and C1, respectively. the parts list and the component loca- drawing. Solder the lead at both pads. tion diagram during construction. Install R33 on an angle as shown, TABLE 2. CONNECTIONS BETWEEN Caution: The pc board uses plated- with one lead tack soldered to the top MODULES WHEN AP-3 IS USED WITH through holes for easy construction. Sol- COR-3. lead of C99, as shown in the detail. dering need be done only on underside SIGNAL RCVR TD-2 AP-3 COR e. Install R28, and solder to the Rcvr Audio E2* E7 of board. However, because it is more board. Then, install C27, tack AP Audio Out E9 E6 difficult to unsolder plated-through Rcvr COS E4* E11 soldering its leads to the leads of R28. boards, be sure parts are in the correct AP COR Out "H" E12 E7 place before soldering. Be careful not to Observe polarity. DTMF Tones "1" E8 interchange parts which look similar, f. Install zener diodes VR1 and DTMF Mute "3" E10 AP-ON Command "4" E13 e.g., resistors with similar color codes. VR2 vertically with cathode bands up, Be sure to observe polarity on as shown in the detail. Tack solder transistors, diodes, electrolytic the upper leads together. n. Check over construction to be capacitors, and ic's. g. Install the ic socket for U1 as sure all parts are installed in proper Note that the pc board was designed shown. The socket has a prominent places and with correct polarity on for a relay which is no longer available. notch in one end. Install the socket diodes and electrolytic capacitors. Therefore, some adaptations are to match the notch shown on the Check all solder connections for bad necessary to use another style of relay. diagram. Plug the 3301 ic into the joints, solder splashes, etc. a. Orient board as shown in the socket, being careful that no pins component location diagram. Be sure bend over. OPTION FOR NO REVERSE the proper side is up. h. Solder ic's U2 and U3 directly to AUTOPATCH. b. Locate relay K1, which is blue the board, orienting as shown. If you wish to prevent any reverse and has four leads. Cut four one inch i. Install transformer T1, and autopatch or calling into the lengths of #22 bus wire, and wrap the solder leads. Autopatch for control purposes, for ends around the relay leads as shown. j. Install potentiometers R1 and example, be cause you are using the Tack solder bus wires to relay leads. R8, checking parts list for proper family telephone line and you need to Be careful not to stress the relay values.