"TTY232" Teletype Loop Supply and RS-232 Interface (90-700-A) =============================================================== Dec 2000, Gil Smith, gil@vauxelectronics Also see: "TTY232-TAP" RS-232 to Teletype Current Loop Interface (90-701-A) Contents: ========= Description Assembly Disclaimer Testing Techno-poop Optional/Future Crapola Applicatons Parts List Description: ------------ This gadget provides eveything you need for connecting teletype machines together in a local loop, and also connecting to a computer via an RS-232 serial port. It provides tty loop power (and current-limiting), and full safety isolation. You can use the box simply as a loop supply for connecting multiple TTYs together, but when you connect a computer's 232-serial (com) port to the interface's 232 port, a program on the computer can then talk to the tty gear. For example, using Bill Bytheway's RTTYArt program (bytheway@foxinternet.net), you can "read" the data from a paper-tape when you run the tape through a TD in the loop -- you can then save the tape data as a disk file. The program can also "send" a disk file out to a tty printer (like an M15 or M28) to print the file out, or to a punch to create a paper tape. Bill's program is primarily designed for reading and writing "art" files -- drawings and pictures created using the characters of the printer. He has created an archive of art files, and created the RTTYArt program to let people read their art tapes for contribution to the archive. Printing an art file is also a great way to test a printer, and demo it to others. A terminal program (dos), which allows manual typing, is available courtesy of Dave Ross (www.hypertools.com/ttysim.zip). It can also talk to the computer's serial port for direct baudot communication down to 45-baud (60 wpm). For Linux boxes, Guido Kueppers (nc-drkugu@netcologne.de) has written awk scripts for direct baudot to a tty serial port. This unit can be built for about $94 if fully populated. You can also build it for less if you don't build all sections, substitute cheaper chassis/ac-line-cord/switches, etc. The board is 4.3 x 4.8 inches, and the chassis is 5 x 10 x 3 inches. Features: 1) High-Voltage (150V) loop supply, 60- or 20-mA loop operation, and four insulated 1/4" jacks for one to four TTYs (M15, M28...). A switch configures the four jacks in series for a local loop of keyboard-contacts and/or selector magnets for various ttys (half-duplex use), or allows one jack to be TTY-TX and the other three to be TTY-RX (full-duplex when using the 232 port). 2) Low-Voltage (30V) loop supply, 20-mA loop operation, and three insulated 3.5mm jacks for one to three TTYs (M32, M33...). The LV loop only operates at 20-mils, and only in half-duplex. 3) RS-232 interface using fully opto-isolated connections to both HV and LV loops. RS-232 transmit signal from the computer is sent to both loops (you may disable 232TX to either loop with a jumper). The computer receive signal is jumper-selectable for monitoring either the HV or LV loop. HV loop may operate in full-duplex or half-duplex mode; the LV loop is half-duplex only. 4) Socket for optional PIC microcontroller -- may be used to provide ascii-to-baudot conversion, baud-rate conversion, auto-line-feed insertion, detection of command sequences, digital or analog i/o, control of an X10 powerline interface (TW523 or PL513) for load control...stuff like that. There are many 28-pin PICs that fit this socket (cheap to pricey). There is also an optional serial eeprom socket (I2C) to use with PICs lacking internal eeprom. If PIC is not installed (which will be the case now, since it is not programmed yet), jumpers connect the 232 port directly to the tty loop interface -- Bill's RTTYArt program can then talk directly to any of the machines. 5) An RS-485 network interface may be used in addition to the 232 interface. This gives a 4000-foot max distance over a twisted-pair line, for a master-slave half-duplex net. Since 485 is a half-duplex net, the PIC is needed to control RX/TX direction of the 485 chip (RX of the chip is TTY transmit). Or, the 485 chip could be jumpered to only receive from the line, for TTY TX-only use over a long cable. 6) Connector for an X10 powerline interface module, can allow the PIC to send X10 commands over the AC wiring to switch TTY motors on/off automatically, and even control lights around your house if you'd like. It can also listen to the powerline for X10 commands (eg: from RF remotes) and do other stuff when certain commands are received. Most people won't care about the micro, eeprom, rs-485, X10, or even the LV loop for the M32/33 machines. That stuff simply does not need to be installed. But the board is flexible, so you can build it the way you need it. Assembly: --------- Inspect the board for shorts/opens before starting (not likely, but it is a prototype pcb). Note that square pads denote negative pins (caps, diodes...), or pin-1 (ICs, connectors...). Use a low-wattage soldering iron with a small tip. Use a rosin-core solder -- there's no need to clean the board with chem-spray (you could goop up the connectors inside). Do the smallest to the largest parts (resistors, caps, chips...). Put sockets on the chips if you'd like. Before you start soldering a part, make sure all leads are sticking through the board. If you need to take something out, clip it off leaving as much lead as possible, then use tweezers to pull each lead out as you heat the pad, then use solderwick to clean solder from each hole. If solder does not easily wick from the hole, drill it out instead -- too much heat will lift pads/traces. Clip leads one at a time so as to not stress pads/traces. Open a nice cabernet, but have a two-glass limit. OOPS: I forgot to ground U101-11 -- this is for forced handshake lines back to the PC, which likely will be ignored by the PC anyway, but jumper U101-11 to U101-15. OOPS: DS102 has the pads backwards -- install as per assembly drawing. OOPS: Square pads showed up as round in a couple of places -- not sure why, since they were correct in the cad file. Assembly drawing shows proper orientations. Lay the board in the bottom of the chassis and mark mounting holes. After you drill 1/8" holes for the mounting standoffs, it will take a bit of measuring and marking to locate the front/rear panel holes, using the mounting hole locations as a reference. Note that the distance between mounting holes and connector centers is in 0.1" increments, to make it a bit easier to measure and mark the holes. Also drill the mounting holes for the power resistors. I mounted them in the right side of the chassis, bolted to the bottom. They still run a bit hotter than I'd like, so I think it might be better to mount them on the inside of the right side panel, and bolt through to a heatsink mounted on the outside of the right side. I'll look for an appropriate heatsink. Position the transformers in the chassis (leaving space for the switch and AC jack), and mark/drill these holes as well. You will need a nibbler to cut the rectangular holes for the switch and AC jack. If you would like the LEDs on the front panel (instead of hidden on the board), drill holes for the mounting rings as well, and solder the LEDs to short lengths of twisted wire. Jazz sax seems to help with the assembly -- I'd recommend Joshua Redmond or Grover Washington. For labelling, I like Avery clear laser labels which are available at an office supply store. They are available in various peel-off label sizes, or as a full sheet. Just print all the text/graphics you want onto the label stock, and cut apart with scissors. You can peel and apply using an xacto knife. If you are not using the full-sheet stuff, print to paper first to make sure you are not printing on a label cut line. Leave the chassis natural aluminum, or paint it a light color to use these labels. They may even make clear inkjet stock (I have not seen any though), which would let you print color labels. You could also use the old dry-transfer stuff, sealing it with a mist of matte fixative from an art supply store. Disclaimer: ----------- This thing has nasty voltages inside. You'll have more fun if you don't kill yourself. Yes, I got bit already. I had the scope ground on the 150V ground, and unplugged a 1/4" tty cable, finding the sleeve in the process. Even though the loops are normally floating (which would have prevented the previous incident), the phone jacks are insulated, and the chassis is grounded, you should turn everything off before changing tty cables. It might be a good idea to wear glasses when you work on this, just in case you have a cap backwards, or something else blows up. I had a tiny sliver of solder, left from drilling a plugged hole, which found its way across 150V, of course -- popped like a frickin' firecracker. Testing: -------- Before wiring the board into the chassis, you should use a meter to check for shorts across the transformer input pads, and across the 150VDC, 30VDC, and 5VDC supplies. Check that the three ground planes are isolated from each other (check this after assembled in chassis also). You should have the AC line ground wired to a ground lug on the chassis, and to the E7 pad on the pcb, which connects the 5V and 232 interface to earth ground (this is also grounded via the mounting standoffs, provided they are metal). The HV and LV loops are completely floating. For testing the 5V section, you can clip your scope/meter ground to the tab of the 7805 regulator. You might want to add ground tabs to the 150V and 30V grounds -- bend a bit of wire into a small circle, and solder the two overlapping ends onto an open spot on the ground plane. When you turn power on, all seven leds should be on. Carefully measure the 150VDC, 30VDC, and 5VDC supplies. You can plug an ammeter into each loop to measure loop currents. For the HV loop, set H201 to both 60- and 20-mA positions; for the LV loop, the current should be 20-mA. First check the HV loop. Connect a PC to the 232 port, and run the RTTYArt program (select proper com port and connect), or the TTYSim program (must be COM1). Select the baud rate of the TTY you will test (eg: 60-wpm/45-baud). Set H201 for 60- or 20-mA, and set H103 to the HRX position. With S200 in the TTY1-4 (Half-Duplex) position, plug a TTY (M15/28...) into any of the four front jacks (if it has a single cable), or into any two of the four front jacks (if it has black and red TX/RX cables). Turn on the TTY232 box and the TTY. When you type on the TTY, it should also print (half-duplex), and the char should show up on the PC screen. When you type on the PC, it should print on the TTY, and also echo back to the PC. Note: I did not get this echoed char at first, until I disconnected the snubber. The snubber keeps the inductive transient down (a voltage spike on the switching transistor collector, when it turns off), but screws up the loop sense circuit. I'll look into different snubber values that are a bit softer. For a full-duplex TTY, switch S200 to the TX/RX (Full-Duplex) position, and plug the TTY's black plug into the TTY1/TX jack, and the TTY's red plug into one of the other three jacks. Turn on the TTY232 box and the TTY. When you type on the TTY, it should not print, but the char should show up on the PC screen. When you type on the PC, it should print on the TTY, but not echo back to the PC. Now check the LV loop. Connect a PC to the 232 port, and run the RTTYArt program (select proper com port and connect), or the TTYSim program (must be COM1). Select the baud rate of the TTY you will test (eg: 110-baud ascii). Set H103 to the LRX position. Plug a TTY (M32/33) into any of the three rear jacks (if it has a single cable), or into any two of the three jacks (if it has TX/RX cables). Turn on the TTY232 box and the TTY. When you type on the TTY, it should also print (half-duplex), and the char should show up on the PC screen. When you type on the PC, it should print on the TTY, and also echo back to the PC. You should burn the unit in for a while, with no TTYs connected, and the cover on. For maximum power dissipation, set H201 for 60-mA, and switch S200 to the TX/RX (Full-Duplex) position. Put in on concrete, away from combustibles, preferrably while you are around as well. Check after it has been running for about an hour to see how hot things are getting. Unplug the unit, wait a minute for things to discharge, and then feel everything. If anything is too hot to touch constantly, it may need to be checked. I think the HV loop power resistors could use a finned external heatsink, but eveything else seems fine on my unit. I'd burn it in for a few days at least. Techno-poop: ------------ This board came about since I wanted to connect my computer to my M15 or M28 (which need a high-voltage loop), or to connect to an M33 (which needs a low-voltage loop). The high-voltage (HV) loop has a 150V loop supply, drop resistors to set 60- or 20-mil loop current (as needed), and insulated 1/4" jacks so you can plug your tty gear into the loop. The low-voltage loop has a 30V loop supply, a drop resistor to set 20-mil loop current, and insulated 3.5mm jacks. The HV loop includes a snubber suggested by Jim Haynes (Bob Weitbrecht's RC from collector to base). The two loops are independent and may be used at the same time, but equipment on the HV loop cannot talk to the LV loop, and vice-versa. I used standard 1/4" phone plugs for the HV loop, and non-standard 3.5mm (1/8") phone plugs for the LV loop, to prevent frying a low-voltage machine by mistake. The 232 port is opto-isolated to both loops, and all power supplies are transformer-isolated from the AC line. The HV and LV loops are floating; the 5V logic and 232 circuitry ground is connected to chassis (earth) ground for safety. The 232 transmit line drives a transistor that opens/closes the loop to "send" characters to the machines in the loop. There is a sense circuit that feeds the loop status (open/closed) to the 232 receive line. The chassis houses the circuit board, the three small power transformers, an AC line jack, four insulated 1/4" phone jacks for HV TTYs, a Full/Half-Duplex switch for the HV loop, three 3.5mm phone jacks for LV TTYs, a DB-9F connector for the 232 port (uses a straight-through M-F cable to PC), and a 6P6C modular jack for an X10 interface module and/or RS-485 twisted-pair. In Full-Duplex mode, the keyboard (or tape-reader) contacts are sensed, and the characters are sent to the 232 port RX line only. Characters from the 232 port TX line are sent to printers (and/or punches). In Half-Duplex mode, typed characters will echo locally on the tty (as well as all other ttys in the loop). Characters sent from the 232 TX line are also echoed on the RX line. According to Don Robert House, the common color conventions for 1/4" TTY phone plugs are red for receive (RX), and black, brown, or green for send (TX). Polarity convention is negative battery for telegraph transmission (since positive battery causes electrolysis in copper cables). Therefore the signal line is negative, and ground is positive. The 1/4" jack convention is tip-negative, sleeve-positive. The polarity should be of no concern on a short local loop, but I tried to keep historical accuracy when possible. Don also noted that of the five level (Baudot/ITA2) teletype machines, about 85% used 60-milliamp selector magnets, 14% used 20-mil, and 1% used 10-mil (US Weather Bureau). Note that 60-mil machines are in reality 62.5 milliamps by design, and that 130VDC is considered the optimum loop voltage. The minimum acceptable loop voltage for these system is said to be around 110 to 120VDC, and the upper end around the NEC safety limit of 199VDC. This design uses 150VDC, since it is readily available using a 115-115V transformer. However, some folks have pointed out that they have successfully used loop supplies as low as 24VDC, with short 60-mil loops, or even 12VDC using short 20-mil loops. I was able to get a 60-mil machine running with 18VDC in the loop. You could put adjustable power resistors in the loops if you wish to set the loop current exactly. You could even mount ammeters in the chassis and wire them into the loop(s). The circuit values I used (transformers/resistors) give approximately 20 mA and 60 mA (not 62.5). Note that the loop supplies are not regulated (will vary with AC line voltage), transformer windings are not always exact (the 24VAC xfrm seemed a bit higher than it should be), and voltage drops of devices plugged into the loop change the loop current somewhat (current will drop a bit with each new device connected). However, I suspect that TTYs have quite a bit of margin of acceptable current range, and that the fixed values are fine for all but the most discriminating folks. If you do change to an adjustable power resistor, just be sure to use one that is rated at the appropriate wattage, and mounted to dissipate the heat. My rule of thumb for power dissipation, is that I should be able to touch a power part and not need to remove my finger (don't get a shock when you do this). If it's too hot to touch, change the design. Quite a few folks pointed out the rationale for the high-voltage loops. First, the higher voltage will keep some of the dust and oil burned off of the keyboard and TD contacts to help keep them clean. Second, the high DC loop supply voltage is needed to overcome the effect of the selector magnet inductance, which impedes the rise in current when going from SPACE to MARK. Using a high voltage in series with a large resistor (to obtain 60- or 20-mils) minimizes the effect of the inductance, permitting the current to rise rapidly, thus preventing deterioration of the receiving selector margin. The circuit will act faster and give less distortion if a higher voltage is used. It was suggested to compare the usable range finder settings using different loop supply voltages -- you would expect to find a much greater range with a higher-voltage loop. I checked into the math: the inductance of the selector coils is significant, and coil voltage is proportional to L*di/dt. But it's technically the loop resistance, not the loop supply voltage, that sets the current waveform in the coil. Of course, to use a larger R, you need to use a larger V, to get the 60 or 20 mA needed. For a series circuit with a voltage source V, resistor R, and inductor L, when initial current (t=0) is zero, the current for t>0 is: -t/T i(t) = (V/R) - (V/R) e where the time constant T = L/R. The first term (V/R) is the drop across the resistor, which will be a constant 60 mA (or 20), by design. The second exponential term affects the leading edge of the waveform, but note that the V/R scaling magnitude is again a constant (0.06 or 0.02) and not actually dependent on V. It is the T= L/R in the exponent that sets the rise time of the waveform, larger R resulting in faster rise times. Optional/Future Crapola: ------------------------ I layed this board out for a 28-pin PIC, with the new flash F87x parts in mind. An 18-pin PIC would have been a good size, except none are yet available with the usart (the F627 and F628 will be nice, but are not shipping yet). I want to use the usart for the 232 port (yes, I have bit-banged 232 on lots of other pics, but I don't wanna anymore). The 28-pin parts with usart that I had in mind for this board are: PIC CODE DATA EEPROM QTY-1 (DigiKey) 16C62B 2K 128 - $4.70 OTP 16C63A 4K 192 - $5.78 OTP 16C66 8K 368 - $8.38 OTP 16F872 2K 128 64 $4.98 FLASH/ISP 16F873 4K 192 128 $8.68 FLASH/ISP 16F876 8K 368 256 $9.38 FLASH/ISP The pricing is for 20 MHz parts, that I plan to run at 16 MHz. I put a 10-pin header on the board for In-System-Programming (ISP) of the flash parts. Standard Flash parts may be reprogrammed, but need a programmer box -- these ISP flash parts allow code to be changed while the chip is in the board. The One-Time-Programmable (OTP) parts also need an external programmer, and are throw-away if code needs to be changed (but are cheaper for volume use). There are UV-erasable/reprogrammable versions of the OTP parts, but they cost more than the ISP parts. My intent for the pic code, is to use the usart for the 232/485 port, and bit-bang the tty interface. Possible code features: - force pass-through (bypass mode -- simply connect 232 to ttys) (switch-selection using pic pin?) - ascii-to-baudot conversion (switch-selection using pic pin?) - buffer 232 data at higher speed (19200 or 9600), to various tty baud rates - automatic CR/CR/LF/LTRS insertion at end-of-line (eg: at 72nd char) (Alan Hobbs pointed out that the European standard is 69 chars, so make it programmable) - enable or disable unshift on space - detection of local command sequences for changing pic operating mode... (not passed to tty -- eg: change tty baud rate, number of eol chars...) - commands to send break, open or close tty line (eg: for external motor control devices) - store programmable params in eeprom - digital i/o (switches, lights, relays...) - analog i/o (measure loop current w/ isolated sensor...) - control an X10 powerline interface (connector avail for TW523 or PL513) (eg: automatically turn tty motors on/off) The 6P6C modular connector is for an X10 powerline interface module (a two-way TW-523 or a one-way PL-513). X10 commands are carrier-current modulated on the AC powerline, and the interface module provides an opto-isolated means for connecting to the line. X10 capability can allow the PIC to send X10 commands to switch TTY motors on and off automatically, using X10 appliance modules. The pic could sense a character and then power up the ttys (or even a specific tty). You could just send a null, or id char, wait a few seconds, then send the text -- or maybe the pic could buffer the text. The pic would power the tty(s) down after a minute or so of inactivity. Could also be used to provide 232-control of lights in the house, detect X10 commands from other devices like RF remotes, etc. It's another future project, but I have done X10 pic code in the past, and it's not too bad. X10 stuff is not high-rel, but it's cheap, and available in 115V/60Hz and 220V/50Hz versions. Applicatons: ------------ Some ideas for connecting TTYs to a computer have been bouncing around on greenkeys in the past -- with the appropriate bits of software, you could do some interesting things: a) run a simple baudot terminal program, like TTYSIM b) read/punch tapes to/from computer files, using the RTTYArt program c) with an ascii-to-baudot converter PIC in the interface, you could make a tty look like a standard pc printer (many applications could print) d) hook to your email program and have certain email (eg: greenkeys) that automatically prints on your tty e) have your computer periodically check for news of your choice (via internet), and print it out on your tty f) have your computer periodically check the local weather (via internet), and print it out on your tty g) have your computer periodically check certain stock prices (via internet), and print it out on your tty (or, better yet, print it out on an old stock ticker) h) or how about an internet "chat" room, where your machine is connected in real-time as the i/o for the chat. This is the internet version of global rtty, with no fading, and no distance limitations! Parts List: =========== Full build: Basic (41.92) + RS-232 (9.27) + HV-Iface (34.06) + LV-Iface (8.75) = $ 94.00 Some cheaper parts may be substituted (chassis, switches...), or you can build only a portion of the circuit. Mouser Electronics www.mouser.com 800-346-6873 DigiKey www.digi-key.com 800-344-4539 Jameco www.jameco.com 800-831-4242 Basic Stuff: ------------ Ref Desc Source Order Number Qty $ Each --- ---- ------ ------------ --- ------ pcb gil 90-700-A 1 15.00 J1 AC jack/fuseholder Mouser 161-0717-1-187 1 2.09 F1 fuse, 1/2A SB, 5x20 mm Mouser 5765-18500 1 0.67 S1 switch, rocker Mouser 107-DS850K-00 1 1.29 chassis LMB 5x10x3 cap box Mouser 537-5103 1 13.12 cover LMB 5x10 cover Mouser 537-5103C 1 4.29 feet bumper, adhesive Mouser 517-SJ-5012BK 4 0.15 pcb mounts standoff, 4-40, 0.5" Mouser 534-2203 4 0.22 4-40 screws, locks, nuts, as needed (pcb and transformers). 2-56 screws, locks, nuts, as needed (chassis resistors). ground lug for chassis ground power cord AC line cord Mouser 173-63101 1 3.98 ----- 41.92 RS-232 Interface and 5V supply: ------------------------------- Ref Desc Source Order Number Qty $ Each --- ---- ------ ------------ --- ------ C100 cap, 100uF, 25V Mouser 140-XRL25V100 1 0.07 C101/C102/103 cap, cer, .1 uF Mouser 21RZ310 3 0.08 C104/105/106/107 cap, 10uF, 50V Mouser 140-XRL50V10 4 0.05 D100 bridge-rect, 400V/1.5A Mouser 583-RB154 1 0.38 D101/102/103 diode, 1N4148 Mouser 625-1N4148 3 0.06 DS100 led, T1, grn Mouser 604-L934GD 1 0.20 J101 jack, DB-9F Mouser 152-3409 1 0.95 or Jameco 104951 (0.55) Q100 xstr, pnp, 2N4126 Mouser 625-2N4126 1 0.09 R100/111 res, 2.7K, 1/8W Mouser 299-2.7K 2 0.08 R101/104/105 res, 4.7K, 1/8W Mouser 299-4.7K 3 0.08 R103/106/107/108 res, 120, 1/8W Mouser 299-120 4 0.08 R109 res, 470, 1/8W Mouser 299-470 1 0.08 R110 res, 1.5K, 1/8W Mouser 299-1.5K 1 0.08 T100 xfrm, 12.6VCT, 2.5VA Mouser 41FG200 1 3.43 U100 reg, 5V, LM7805CT Mouser 511-L7805ACV 1 0.40 U101 RS232 iface, MAX232 DigiKey TC232CPE 1 2.25 or Digikey MAX232CPE (3.31) or Digikey MAX232ACPE (4.88) ----- 9.27 High-Voltage (150V) Loop Supply and 20/60-mA Interface (M15, M28...): --------------------------------------------------------------------- Ref Desc Source Order Number Qty $ Each --- ---- ------ ------------ --- ------ C200 cap, elect, 100uF/200V Mouser 140-XRL250V100 1 1.29 or DigiKey P5338 C202 cap, film, .05uF/200V Mouser 140-PF2D503K 1 0.24 D200 bridge-rect, 400V/1.5A Mouser 583-RB154 1 0.38 D201/202 zener, 5.1V, 1W Mouser 625-1N4733A 2 0.14 D203 diode, 1N4148 Mouser 625-1N4148 1 0.06 DS200/202 led, T1, grn Mouser 604-L934GD 2 0.20 DS201 led, T1, yel Mouser 604-L934YD 1 0.16 J200/201/202/203 jack, phone, mono/sw, 1/4" Mouser 550-10284 4 0.53 Q200 xstr, npn, 300V, 0.5A Mouser 511-MJE340 1 0.52 R200 res, 100K, 1/2W Mouser 293-100K 1 0.08 R201/204/205/206 res, chassis, 5K, 10W Mouser 284-HS10-5K 4 1.99 R202/212 res, 470, 1/8W Mouser 299-470 2 0.08 R203/207 res, 2.7K, 1/8W Mouser 299-2.7K 2 0.08 R208 res, 150K, 1/4W Mouser 291-150K 1 0.07 R209 res, 47K, 1W Mouser 294-47K 1 0.14 R210 res, 1.5K, 1/8W Mouser 299-1.5K 1 0.08 R211 res, 100K, 1/8W Mouser 299-100K 1 0.08 S200 switch, DPDT, tog Mouser 10TF160 1 3.89 T200 xfrm, 115V-dual, 25VA Mouser 553-VPS230110 1 15.40 U200/201 optoisolator Mouser 512-4N37 2 0.30 ----- 34.06 Low-Voltage (30V) Loop Supply and 20-mA Interface (M32, M33...): ---------------------------------------------------------------- Ref Desc Source Order Number Qty $ Each --- ---- ------ ------------ --- ---- C300 cap, 100uF, 63V Mouser 140-XRL63V100 1 0.12 D300 bridge-rect, 400V/1.5A Mouser 583-RB154 1 0.38 DS300/302 led, T1, grn Mouser 604-L934GD 2 0.20 DS301 led, T1, yel Mouser 604-L934YD 1 0.16 J300/301/302 jack, phone, mono/sw, 3.5mm Mouser 16PJ528 3 0.67 Q300 xstr, npn, 2N4124 Mouser 625-2N4124 1 0.09 R300 res, 15K, 1/8W Mouser 299-15K 1 0.08 R301 res, 2.7K, 1/8W Mouser 299-2.7K 1 0.08 R302 res, 1.5K, 1W Mouser 294-1.5K 1 0.14 R303 res, 22K, 1/8W Mouser 299-22K 1 0.08 R304 res, 10K, 1/8W Mouser 299-10K 1 0.08 R305 res, 1K, 1/8W Mouser 299-1K 1 0.08 R306 res, 100K, 1/8W Mouser 299-100K 1 0.08 R307 res, 470, 1/8W Mouser 299-470 1 0.08 T300 xfrm, 24VCT, 5VA Mouser 41FK200 1 4.29 U300/301 optoisolator Mouser 512-4N37 2 0.30 ----- 8.75 Optional stuff: --------------- C108 cap, cer, .1 uF Mouser 21RZ310 1 0.08 C109/C110 cap, cer, npo, 27 pF Mouser 140-50N2-270J 2 0.07 J100 power jack, 2.1mm coaxial Mouser 16PJ031 1 x J102 jack, modular, 6P6C Mouser 154-UL623-6PCB 1 x R102/112/113 res, 4.7K, 1/8W Mouser 299-4.7K 3 0.08 U102 RS-485 iface, MAX485CPA DigiKey MAX485CPA 1 2.76 (or LTC485CN8) U103 uC, PIC16F876 (or other) DigiKey PIC16F876-20/SP 1 11.75 U104 eeprom, 24Cxx Y100 xtal, 16 MHz Mouser 559-FOX160-20 1 x C201/203/204 cap, film, .001uF/200V Mouser 140-PF2D102K 0-3 0.17 C301/302 cap, cer, .001uF 6-pin IC socket Mouser 571-3902611 4 0.07 8-pin IC socket Mouser 571-3902612 2 0.07 16-pin IC socket Mouser 571-3902614 1 0.08 28-pin IC socket (0.3") Mouser 571-23825713 1 0.18 Led panel-mounting ring for T1 led Mouser 606-CMP100 0-7 0.13 header jumpers Mouser 151-8010 x 0.12 header strip (dual-row) Cable for LV TTY (black 3.5mm phone plug/cord) Mouser 172-2106 1+ 1.63 Cable for serial port (DB9-F to DB9-M), 6ft Jameco 25700 1 4.95 Cable for serial port (DB9-F to DB9-M), 10ft Jameco 148515 1 6.95 ------------------------------------------------------------------------------------------