Switch 1 currrent loop
| Numb | Active | Passive | Direction |
|---|
| 1 | On | Off | Receive - input |
|---|
| 2 | Off | On | Receive - input |
|---|
| 3 | On | Off | Receive - input |
|---|
| 4 | Off | On | Receive - input |
|---|
| 5 | On | Off | Receive - input |
|---|
| 6 | On | Off | Transmit - output |
|---|
| 7 | Off | On | Transmit - output |
|---|
| 8 | On | Off | Transmit - output |
|---|
| 9 | Off | On | Transmit - output |
|---|
| 10 | On | Off | Transmit - output |
|---|
|
Switch 2 RS232
| Numb | DTE | DCE |
|---|
| 1 | On | Off |
|---|
| 2 | Off | On |
|---|
| 3 | On | Off |
|---|
| 4 | Off | On |
|---|
| 5 | Off | On |
|---|
| 6 | On | Off |
|---|
| 7 | Off | On |
|---|
| 8 | On | Off |
|---|
| 9 | Off | On |
|---|
| 10 | Not used | Not used |
|---|
|
![[Circuit board]](/grundig/r422.jpg)
![[Back]](/grundig/r422b.jpg)
![[Base]](/grundig/r422m.jpg)
