Modem Circuits
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Modems are devices that connect either remote devices to a computer, or two or more computers to each other. Their connection is usually wired. The GSM modem we present is wireless. It can connect two computers, a computer with the internet or even be the central unit for a data acquisition system. Generally the construction is a GSM phone without keys and display. Its operation is easily accomplished by its serial door with AT commands. The... .
The circuit has been designed to accommodate all those who dedicate many hours of their lives by exploring the endless pages of this site. Despite the fact that it consists of only three components (Most were not little!), Is able to provide an indication of whether it actually released the telephone line after a long connection via modem to the network. This can be particularly useful, since there In many cases, the computer claims that the... .
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The popularity and easy access of RS-232 ports lend them to many communication projects. You can use a port as is” or as a tiny parallel port when the exchange uses only control lines. Before the asynchronous serial-data transfer between two devices can take place, you must ensure that both devices are configured to the same data format and transmission rate. Usually, the OS utility or application program on the host computer performs this... .
Here is some experimental hardware and software to transmit and receive AX.25 packets. It is essentially a PIC-E clone designed around a Atmel AT90S2313 with a few extra bells and whistles. I had picked up a couple of MXCOM MX-614s at the TAPR display (I also joined TAPR) at the Dayton Hamvention, and I needed a project to try them out on. I had designed many projects around Microchips PIC series micros, but had recently started... .
First of all you have to build one cable adapter to connect the female 9pins connector of the modem, with female 9pins connector of the base of E-10G HPC. To build the null modem cable you will need: 2 male connectors with 9 pins. 15cm cable with 7 wires. The schematic at the left , its show how to connect the wires. When you finish it, you can connect the modem with E-10G. I have test it with: ISDN NetMod ( From Intracom, its used by the... .
The transformer is a 600:600 ohms transformer (also named 1:1 ratio 600 ohm transformer) : more or less the same number of turns on both primary and secondary coils, and optimized to work at 600 ohms load. Selectronic sells one here. I measured the primary and secondary coils on the one from Selectronic: about 75 mH inductance and 50 ohms .
This design circuit is shows an LM1893 power line modem circuit. This circuit is used to transfer information between remote locations by using the power mains. This circuit uses LM1893 that is used as a power line interface for half-duplex (bi-directional) communication of serial bit stream of virtually any coding. This is the figure of the circu .
The KD2BD Pacsat Modem is a low cost, high performance 1200 bps BPSK modem designed to interface between a packet radio terminal node controller (TNC) and an amateur satellite ground station, and allows full-duplex access to the 1200 baud "Pacsat" constellation of amateur satellites. The KD2BD Pacsat Modem consists of a 1200 bit per second BPSK de .
Be sure to use the correct 9-pin `D` type connector so the pins fit in the board. The two outer holes for mounting the 9-pin `D` type connector should be 3mm Dia. and the holes for the pins are 1. 2mm Dia. The PCB is also tailored for a PCB mounting 5-pin DIN socket. These holes should also be 1. 2mm Dia. All other holes on the PCB are 0. 9mm Dia. The 22K resistor close to the 5-pin DIN socket is .
RF is just way too cool not to use in your designs. But if you`re a newbie like me it is difficult to successfully build solid RF transmitters and receiver.. .
This is a circuit for an LM1893 power line modem circuit. This circuit is used to transfer information between remote location by using the power mains. This circuit uses LM1893 that is used as a power line interface for half-duplex (bi-directional) communication of serial bit stream of virtually any coding. This is the figure of the circuit; To g .
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CMX7031Q1 is a sub package of CMX7031, If you need see the description, please click CMX7031. If you need CMX7031Q1`s datasheet, please download it from below. By Consumer Microcircuits Limited .
The CMX867A is a multi-standard modem for use in telephone based information and telemetry systems. Control of the device is via a simple high speed serial bus, compatible with most types of C serial Interface The data transmitted and received by the modem is also transferred over the same serial bus. On-chip programmable Tx and Rx USARTs meeting .
This RS-232 RS-232 /a> to RS-485 protocol converter uses two products for a complete operational system. The circuit will comply with all EIA and ITU specifications for RS-232 RS-232 /a> to RS-485 RS422 conversion. This is a rugged design that will handle +/-15kV ESD levels on the bus pins. The design is compatible with 3. 3V or 5V systems requirin .
This application note describes the operation and features of the FAN7601. This device is a BCDMOS programmable frequency current mode PWM Controller which is designed for off-line adapter applications and auxiliary power supplies. To reduce power loss at light and no load, the FAN7601 operates in burst mode and it includes a start-up Switch to re .
The NCP5080 product is a high voltage boost driver dedicated to the Xenon power flashes. The built-in DC/DC converter is based on a flyback structure with an external transformer to adapt any range of high voltage demand. The external feedback network makes possible to dynamically adjust the output voltage. .
As transformer a toroidal transformer (2x12V 15VA) is used, because this gives much less energy losses then an E-I core transformer as used in the original mains adaptor (for more info, click here ). .
Doing a project on GSM. In that i want to detect the key pressed at the other side on active call. I am trying with a dtmf decoder circuit at speaker output but it is not working. Plz if any one has any other idea or solution plz reply. .
Have you ever connected two PCs together via modems using a twisted pair cable and nothing happened? That s because the modems are expecting a phone line.. .Related Categories
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