Single-chip modem meets low-speed needs
By Bill Schweber -- EDN, January 24, 2002
High-speed modems may get the headlines, but applications such as security and monitoring don't need or can't afford that speed. To meet those lower-speed needs, Xecom's 2400-bps XE2420 modem comes in a surface-mount package measuring less than 1 in. (25 mm) on a side and 0.29 in. (7.4 mm) high. The package contains a modem controller, an operating ROM, an analog front end, and an interface DAA (data-access arrangement), functioning as a specification-compliant modem using the industry-standard AT command set.
The 24-lead, sealed, hybrid device with a 68-pin-PLCC footprint can unobtrusively share a phone line. It checks for line activity before and during use, so that it doesn't interfere with calls in progress or any calls users dial while the modem is in use. The modem also includes standard features, such as ring detection, loop-current-holding circuit, hook switch, surge protection, and telephone-line transformer. Power consumption is 330 mW in operation and less than 1 µW in power-down mode. The XE2420 meets FCC part 68 and UL60950 requirements and costs less than $20 (10,000).
Xecom Inc, 1-408-945-6640, www.xecom.com.
