 
				
				 
				
				
			| Function | Number of Channels | Operating Temperature | Operating Voltage | |
|---|---|---|---|---|
| SDM-SIO2R  | Expands the serial I/O interface via Synchronous Device for Measurement (SDM) communications on a data logger | 2 | -40° to +70°C | 
 | 
| SDM-IO16A  | Expands the digital input and/or output capability of a data logger. | 16 | -40° to +70°C | 12 Vdc (nominal 9 to 18 V) | 
| Function | Number of Channels | Operating Temperature | Operating Voltage | |
|---|---|---|---|---|
| SDM-SIO1A  | Expands the number of serial devices that can communicate with a data logger. | 1 | -40°C to +70°C (standard) | — | 
| SDM-SIO4A  | Expands the number of serial devices that can communicate with a data logger. | 4 | -40° to +70°C (standard) | — | 
| MD485  | Permits a PC to address and communicate with one or more data loggers over a distance of up to 1,200 m. | — | 
 | — | 
| LLAC4  | Increases the number of low-level ac signals that a data logger can monitor. | 4 | — | — |