RS-422 and RS-485 computer adapters / Converters
When selecting a computer interface to a broadcast device, the key is that some of the 422/485 adapters do not have SMPTE 9-pin wiring and you may need to make an adapter so that the cables you use are standard straight through pinouts. Your adapters should always reside directly on the 422/485 connection from your device so that all wiring in your facility will be SMPTE standard. This consistency will pay off when troubleshooting later as devices are swapped around.
Below are a few of the companies that supply adapters for use in the broadcast industry. This list is not complete and I am not making any recommendations as to your choice of vendors, this document is only to provide you with the information you might need to make your choices. Let me know if you find others that should be linked.
contact 24 at chibiconsulting dot com
SMPTE compatible pinouts
- http://www.addenda-elect.com
SMPTE master pinout, controls VTR and other devices.
- http://www.antona.com
SMPTE compatible master or tributary pinout. * If optional power is not applied. *
| Antona Pinouts (SMPTE compatible type*) |
|---|
| Master |
|---|
| DB9 | Function | Identification |
| 1 | GROUND | ground for RS-422 and/or external power |
| 2 | RC- | RS-422 minus side input |
| 3 | TX+ | RS-422 plus side output |
| 4 | | -not used- |
| 5 | GROUND | ground for RS-422 and/or external power |
| 6 | | -not used- |
| 7 | RC+ | RS-422 plus side input |
| 8 | TX- | RS-422 minus side output |
| 9 | +V | Optional +6V to +9V DC @ 100ma |
|
| Slave/Trib |
|---|
| DB9 | Function | Identification |
| 1 | GROUND | ground for RS-422 and/or external power |
| 2 | TX- | RS-422 minus side output |
| 3 | RC+ | RS-422 plus side input |
| 4 | | -not used- |
| 5 | GROUND | ground for RS-422 and/or external power |
| 6 | | -not used- |
| 7 | TX+ | RS-422 plus side output |
| 8 | RC- | RS-422 minus side input |
| 9 | +V | Optional +6V to +9V DC @ 100ma |
|
- http://www.blastronix.com/index.html
SMPTE compatible master or tributary pinout.
| Blastronix Pinouts (SMPTE compatible type*) |
|---|
| Master (J10 Installed) |
|---|
| DB9 | Function | Description |
| 1 | GND | Ground |
| 2 | RX- | RS-422 minus side input |
| 3 | TX+ | RS-422 plus side output |
| 4 | NC | -not connected- |
| 5 | NC | -not connected- |
| 6 | GND | Ground |
| 7 | RX+ | RS-422 plus side input |
| 8 | TX- | RS-422 minus side output |
| 9 | NC | -not connected- |
|
| Slave/Trib (J10 Removed) |
|---|
| DB9 | Function | Description |
| 1 | GND | Ground |
| 2 | TX- | RS-422 minus side output |
| 3 | RX+ | RS-422 plus side input |
| 4 | NC | -not connected- |
| 5 | NC | -not connected- |
| 6 | GND | Ground |
| 7 | TX+ | RS-422 plus side output |
| 8 | RC- | RS-422 minus side input |
| 9 | NC | -not connected- |
|
- http://www.kksystems.com/
Web site lists Sony professional compatible RS422 pinout. (*Sony complies with SMPTE Standard)
Non-SMPTE pinouts; however, adapter available
- http://www.sealevel.com
A PC with Sealevel COMM PCI adapter (Part# 7201 or 7204) or USB SeaPORT (Part# 2202, 2203, 2402, or 2403), connected to Studio Gear with a Sealevel CA190 cable will be SMPTE compatible.
The CA190 cable is available for use with any Sealevel DB9 RS-422 serial adapter for SMPTE conversion.
| Native Pinout (Not SMPTE) |
|---|
| Signal | Name | Pin | Mode |
|---|
| GND | Ground | 5 | - |
| TX+ | Transmit Data Positive | 4 | Output |
| TX- | Transmit Data Negative | 3 | Output |
| RX+ | Receive Data Positive | 1 | Input |
| RX- | Receive Data Negative | 2 | Input |
| 5V/12V | Power selected by E1 | 9 | Output |
Non-SMPTE pinouts
- http://www.bb-elec.com (Note, some external adapters from B&B may have SMPTE pinouts available, verify with them.)
| Pinouts (Non SMPTE) |
|---|
| Name | Description | Direction | DB-9 |
|---|
| RD(A)- | Receive Data A | Input | 1 |
| TD(B)+ | Transmit Data B | Output | 2 |
| TD(A)- | Transmit Data A | Output | 3 |
| GND | Signal Ground | ------ | 5 |
| RD(B)+ | Receive Data B | Input | 9 |
Undetermined pinouts
Appendix A SMPTE 207m summary
| SMPTE 207m Interconnection summary |
|---|
| |
| SMPTE 207m 422 master on db9 |
|---|
| 1 | Frame Ground |
| 2 | Receive 'A' - |
| 3 | Transmit 'B' + |
| 4 | Transmit common Ground |
| 5 | Spare |
| 6 | Receive common Ground |
| 7 | Receive 'B' + |
| 8 | Transmit 'A' - |
| 9 | Frame Ground |
|
| SMPTE 207m 422 tributary on db9 |
|---|
| 1 | Frame Ground |
| 2 | Transmit 'A' - |
| 3 | Receive 'B' + |
| 4 | Transmit common Ground |
| 5 | Spare |
| 6 | Receive common Ground |
| 7 | Transmit 'B' + |
| 8 | Receive 'A' - |
| 9 | Frame Ground |
|
