User guide

C-1

Appendix C. Specifications

Data rates: up to 38,400 baud (limited by datalogger)

Size: 63 x 55 x 17mm (L x W x D), excluding mating D connectors

Operating environment: -25°C to +50

°C, 0-95% RH (non-condensing)

Connector pin assignments: see Tables C-1 and C-2

Power requirements: sources power from datalogger 5V supply via 9-way

interface.

Typical current consumption

• <100µA with no RS232 load and pin 11 not connected

• 2.2mA with RAD-SRM and no communication

• 9.3mA with RAD-SRM, datalogger in communications mode, but low

communications activity

• 10.2mA with RAD-SRM, high communications activity

Current consumption when driving other RS232 modems will vary with the

number of lines connected and the input impedance of the inputs. With 3 inputs

connected (DTR, RTS and Tx from the SC932C), of the minimum 3k

Ω input

impedance, and high communications activity the consumption may be up to

16mA.

RS232 output levels

• RTS 4.2 - 4.5V with 3kΩ load – quiescent state (ME low)

• RTS full power 7 - 9V with 3kΩ load (ME high)

• DTR 7.5 - 9.5V with 3kΩ load (8.8V typical with RAD-SRM); short circuit

current 30mA typical

• Tx greater than ±5V with 3kΩ load

RS232 input thresholds Rx and RI

• Input low 0.8V minimum

• Input high 2.4V maximum

• Input resistance 5KΩ

Pin 11, power control input thresholds

• Input low 1.3V maximum (normal power mode)

• Input high 3.5V maximum (to enable high power mode)

• Input resistance greater than 10kΩ

• Maximum input voltage 20V

Time-outs

• Minimum RING IN pulse width to generate a ring signal to the datalogger is

20µs

• Minimum delay between ME going low and RING IN enable is 0.5s (1s

typical)