What is Modem Chipsets?
| Identifying a Modems Chipset |
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An increasingly popular feature in industrial applications is the ability to remotely access equipment for diagnostic, and/or upgrade purposes. However it is a popular misconception that choosing the fastest available modem will result in the quickest data download time, and hence the shortest telephone connection. In fact, due to the time associated with training up a modem after a connection has been established, for transmitting small quantities of data, a "Slower" modem can actually result in a shorter telephone connection. Many applications exist where the data packets are sufficiently small to benefit from the faster training times associated with these so called "Slower" modems. TDK Semiconductor manufacture a range of modem data pumps compatible with the ITU standards V.21 (300 bps), V.22 (1200 bps), V.22bis (2400 bps) and V.23 (1200/75 bps). A V.21 modem typically starts to transmit immediately it receives an answer tone, V.22 takes two and a half to three seconds extra to synchronise, V.22bis takes five seconds, but the worst startup delay is experienced by V.32 which can waste up to 10 seconds on training alone, before a single byte is transmitted. Data correction and compression handshakes can extend these timings even further before any data is transmitted. Identifying a Modems Chipsets In order to identify your modem chipset: Using a terminal package such as Bitcom, type in AT+FMFR?. You should get a response naming the chipset. If the response is ERROR, type in ATI6. If the response begins with RC, the chipset is Rockwell. Otherwise the response will mention Texas Instruments. |
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