You are right that the DS275 is not a perfect replacement for a MAX23X chip.

I use them for two reasons.

1. Smaller package size - a 8 pin device is less of a problem to work with than a 18 pin MAX232 (or 20 for a MAX233). Its more expensive (and harder to get though).

2. Few serial circuits need 'full spec' RS232 signals (+/- 12 volt signals), the DS275 can only provide a 'positive voltage' as high as the voltage you give it, for most applications this is 5 volts, so the signal won't travel too far, however for most applications a 5 volts serial signal is quite robust enough - many laptops do the same and only generate +/- 5 volts on the serial port.

The DS275 only provides TX and RX not CTS,RTS etc - these signals are generally optional and not used for most Serial interfaces these days.

However, I gather the GPS BG micro are selling does output pulses for its PPS - using this would require a full MAX23X chip.