15 PIN D-SUB MALE
RJ45 MALE CONNECTOR
REDCOM (REDCOM Laboratories, Victor, NY) military and government circuit-switch platforms — including the HDMS, SLICE, and HDX series — provide T1 span interfaces on DB-15 male connectors conforming to ANSI T1.403-1999, carrying 1.544 Mbps DS1 signals on 100 Ω balanced twisted pair. The Promina 800 chassis, manufactured by Network Equipment Technologies (NET), accepted slide-in trunk modules including the DITS (Deployable Integrated Transport Suite) DS1 card, whose line-side physical connector is an RJ-45/RJ-48C 8-position jack. This cable bridges the two interfaces using the standard T1 transmit and receive pairs: RJ-48C pins 1 & 2 carry the receive pair and pins 4 & 5 carry the transmit pair, corresponding to DB-15 pins 1, 3, 9, and 11 in the industry-standard mapping.
| D-SUB 15 Pin | RJ-45 Pin |
|---|---|
| 1 | 1 |
| 2 | 9 |
| 4 | 3 |
| 5 | 11 |
Notes
Both connectors are male; the REDCOM equipment presents a DB-15 male T1 span port, and the Promina DITS module presents an RJ-48C male jack facing the backpanel cable side. The four active RJ-48C conductors follow ANSI T1.403 pair assignments: pins 1 & 2 (receive tip and ring) and pins 4 & 5 (transmit tip and ring). The DB-15 side uses the standard T1 DB-15 mapping in which pin 1 is TX Tip, pin 3 is RX Tip, pin 9 is TX Ring, and pin 11 is RX Ring. TX and RX are crossed between the two connectors as required for a straight-through connection between DTE-oriented endpoints. Unused RJ-48C pins (3, 6, 7, 8) carry no signal in this application.
Signals
- TX Tip (DB-15 pin 1 / RJ-45 pin 1) — transmit tip of the 100 Ω balanced T1 pair, positive polarity
- RX Tip (DB-15 pin 3 / RJ-45 pin 9) — receive tip of the 100 Ω balanced T1 pair, positive polarity; function not publicly documented for pin 2 of DB-15 in this cable
- TX Ring (DB-15 pin 9 / RJ-45 pin 3) — transmit ring of the 100 Ω balanced T1 pair, negative polarity
- RX Ring (DB-15 pin 11 / RJ-45 pin 5) — receive ring of the 100 Ω balanced T1 pair, negative polarity
References
- Promina 800 Installation and Maintenance (Part No. 033720-307 Rev A, Release 3.x7) — Network Equipment Technologies, Inc., 2006