Hi Sumitava,
You can configure router as Frame relay switch. You can have DTE or DCE cable and there is no specific requirement in cable type for frame relay switch.
1. Enable "frame-relay switching" globally
2. Enable "encapsulation frame-relay" under all serial interface connected to other frame relay DTEs.
3. Enable "frame-relay intf-type dce" under all serial interface on frame relay switch.
4. Configure "frame-relay route interface serial
HTH,
Nagendra