Texas Instruments
the max232 device is a dual driver/receiver that includes a capacitive voltage generator to supply tia/eia-232-232-f voltage levels from a single 5-v supply. each receiver converts tia/eia-232-f inputs to 5-v ttl/cmos levels. these receivers have a typical threshold of 1.3 v, a typical hysteresis of 0.5 v, and can accept 30-v inputs. each driver converts ttl/cmos input levels into tia/eia-232-f levels. the driver, receiver, and voltage-generator functions are available as cells in the texas instruments linasic library.
Premier Farnell
transceiver, 5v; line/bus driver/receiver/transceiver type:rs-232; interface type:rs-232; data rate:120kbps; no. of channels:2; current, supply:8ma; voltage, supply min:4.5v; voltage, supply max:5.5v; termination type:through hole; case style:dip; no. of pins:16; operating temperature range:0°c to +70°c
http://grh.premierfarnell.com/grh.aspx?mid=1001023&sku=MAX23... 
