Compaq Aero wiring

A few weeks ago I bought a original compaq aero serial cable. Now I am trying to put 5V through the serial cable, but the compaq doesn't seem to get the 5V. On the serial poles I use the number 5 as the ground and number 8 as the +5V. Anyone knows why it doesn't work? (I tried the original way by putting 5V trough the powercable and then the flashlight bleeps, so the 5V-power and the compaq are OK).

Greetings,

Standard serial cable does not supply power. Pin 8 is Request (or Clear) To Send signal.

Henryk Birecki

*****

The power pins are not wired in the standard Compaq Aero 1500 serial cables. They are only wired in the drop in base cable.

Don't bother cutting the cable to get to the wires, there are no power wires on the Aero end connector.

It is possible to open the Aero end connector to verify this but be very careful, the connector is fragile and hard to work with.

I'd agree with the fragile and hard to work with, but on the serial cable I modified for 5V, there were at least ten wires in the cable. We only need four.

As Gnd, Send and Receive are already connected, the 5V was the one that needed re-soldering. Us as small a soldering iron as you can and make sure to shrink wrap the wires to prevent shorting between them. There's also a product that's liquid electrical tape that you can paint on anything to form a insulation barrier. I found in it in the electrical section of a HomeDepot, but I'm sure it's not that hard to find.

FIRST CHECK the three connections with both connectors still on the cable. This helps as you can identify RXD and TXD and GND. Unfortunately they're all symmetrical on the 1550 end (ie on the last pin or the seventh one from the end!) I think the pin count on the 1550 end was from left to right as you looked at the connector from the front as it's plugged into the Compaq. I'd use pin #17 as your target, as the 'wrong' way would be pin #2 which is not connected anyway! If you have a drop-in cradle and AC adapter, try measuring the 5V to be sure. Be VERY careful not to short it to anything while testing. I didn't do this step, but got it right first time anyway.

I cut off the serial (DB9) end and used the 1550 end and bare wires with a Ohm meter to identify which colour wires were GND,TXD,RXD and then opened up the 1550 end to see which wire was closest (and unused for the other three signals) to re-wire it to the 5V pin on the connector.

Here are the 1550 end pin assignments:

Aero 1500/2100 connector pinout. Pin - Signal Name, Description 1 - GND, Power Ground 2 - (NC), (no connection) 3 - VCC3, VCC3 Power Output 4 - (NC), (no connection) 5 - CTS, RS-232 Clear To Send 6 - DSR, RS-232 Data Send Ready 7 - RXD, RS-232 Receive Data 8 - DCD, RS-232 Data Carry Detect 9 - VSTANBY, Pull up to VSTANBY 10 - RTS, RS-232 Request to Send 11 - DTR, RS-232 Data Terminal Ready 12 - TXD, Rs-232 Transmit Data 13 - RI, RS-232 Ring 14 - M_ISET2, Battery Charge Setting 2 15 - *Cradle_IND, Cradle Inserted 16 - C_ADP_IN, DC Power from AC Adapter 17 - C_ADP_IN, DC Power from AC Adapter 18 - GND, Ground

Search for 'compaq cable pin' in rec.aviation.soaring at http://www.google.com/advanced_group_search?hl=en to get a list of related e-mails.

Just in case you decide to wire the power yourself, here are the Aero connector pin assignments. I received this data from Compaq. ( I know it's been posted before).

The allocation of 5 volt power to pin 8 of the DB9 connector is a Cambridge modification of the standard connector pin assignment. Power is provided on this pin by GPS NAV and 302.

I dont remember if DB9 pin 8 is wired on the Aero serial cable. If is is wired you may have damaged the Aero by putting 5 volt power on an inappropriate pin.

(To clarify my first post - power is wired to the drop in base connector but it goes to the power jack, not to a pin on the serial cable DB9).

Pin - Signal Name, Description 1 - GND, Power Ground 2 - (NC), (no connection) 3 - VCC3, VCC3 Power Output 4 - (NC), (no connection) 5 - CTS, RS-232 Clear To Send 6 - DSR, RS-232 Data Send Ready 7 - RXD, RS-232 Receive Data 8 - DCD, RS-232 Data Carry Detect 9 - VSTANBY, Pull up to VSTANBY 10 - RTS, RS-232 Request to Send 11 - DTR, RS-232 Data Terminal Ready 12 - TXD, Rs-232 Transmit Data 13 - RI, RS-232 Ring 14 - M_ISET2, Battery Charge Setting 2 15 - *Cradle_IND, Cradle Inserted 16 - C_ADP_IN, DC Power from AC Adapter 17 - C_ADP_IN, DC Power from AC Adapter 18 - GND, Ground

Hi,

We have cables that would work nicely for what you're trying to do. Cumulus Soaring Supplies - http://www.cumulus-soaring.com

They are a little more expensive than buying the connectors and doing it yourself. We do not apologize for that. We think we add value in several ways. First, the cable connectors have very small pins which are difficult to solder to. We use high quality cable which is shielded so that data signals don't create noise for your radio. All wire ends have shrink-wrap tubing so that they won't short out when under shock loads. Each cable is tested by us. Also, we stand behind our products and can make custom cables for unique applications.

Good Soaring,

Paul Remde