These ultra small modules are designed for PCB through-hole mounting and are 1.35" x 1.38" x 0.61" (nominal, 0.55" upon request) in size. The HS Modem family requires only two external interfaces: a CCITT V.24 serial interface for direct access to a UART, and a Tip and Ring RJ-11C Jack for the PSTN line connection. The HS Modem can be controlled with industry standard AT commands and is compatible with available industry communication software.