While RS-232 speeds have gone up to 1 MB/s, voltages have gone down to 5V or 6.6V and the 25-pole standard is often replaced by 9-pole solutions. For such circumstances, Comtest 100DLX RS-232 breakout box has two circuits testing high-speed signals and uses ultra-bright LEDs to cope with the lower voltages; it also comes with four 9/25-pole adapters. The unassigned monitors work up to 2.5 MB/s and have a pulse trap function. One of the monitors tests voltage strength of 0.3V, 2V, 3V, 4V and 6V. The instrument can work for more than 40 hours on a single 9V battery and has a built-in circuit generating -9V and two 3 kiloohm terminators. The 50 in-line monitors (100 LEDs) are signal-powered, which means the unit is fully operational even without batteries. Along with breaking lines, the breakout box can test current loops of 4, 10, 20 and 60 mA and ground potential difference down to 0.3V.