Yes, in fact Autocom has headset leads and helmet "looms" specifically designed to accommodate in-ear (monitor) speakers, which can be used use with current as well as older systems.
In-ear speakers can be the basic "ear bud" style that come with MP3 or iPod music players, or they can be the off-the-shelf or custom made type that are made to fit internally in the ear canal.
Standard "ear bud" types of speakers work fine, but these generally sit just inside the ear entrance, and they often do not stay in place after putting on a helmet. Ear bud speakers also do not cut out or remove a lot of the external noise that comes in via the helmet.
In-Ear speakers that are inserted just inside the ear canal are normally preferred as they tend to remove a lot of the external noise.
Custom made in-ear speakers (or earplugs) are made by injecting silicone into the ear which sets hard. The silicone is then fitted with tubing and speakers which allows the audio to be heard.
Other off-the-shelf in-ear speakers can also be purchased at most electronic outlets. These normally have one or two sets of different sized silicone tips which also fit into the ear canal.
Important: Obviously care should be taken with volume levels when using any type of speakers. Science might be able to grow ears on the back of mice, but your actual hearing is hard to replace... except if you are Jaime Sommers (i.e. The Bionic Woman).
Most in-ear speakers come with a 3.5mm male plug which is the same that plugs into music players (MP3, etc). The basic idea for using in-ear speakers is that the sound from the Autocom system is diverted from the Autocom system to the in-ear speakers.
Basically the There are two options available for connecting in-ear speakers.
Part 2091 is a helmet loom which is installed inside the helmet. This loom is used to replace the standard Autocom headset inside a helmet. The loom is made up of 4 leads: two leads with small red connectors are used inside the helmet to connect the microphone and Ambient Noise Sensor.
The red connector for the microphone is required to allow the users voice to be sent back to the Autocom system. The red connector for the Ambient Noise Sensor is require if using the headset loom with either the Autocom Super Pro AVi or Super Pro Automatic systems. If using the loom with other Autocom systems, than a small "Loop" plug is required... this is included with the loom.
The other two leads are left outside the helmet. One lead has a 7-pin DIN plug which is used for connecting to the Autocom system as usual, and the other smaller lead has a female 3.5mm jack, which connects to the in-ear speakers.
When using the above Headset Loom (Part 2091), the in-ear speakers must obviously be inserted first before putting on the helmet.
Part 2130 is a Coiled Extension Lead with a 3.5mm female jack mounted on the lead. This lead is used just like a standard extension lead (Part 2134 or 2138).
There is a small box near the upper end of the lead which has the female jack on it.
The Coiled Extension Lead (Part 2130) allows the user to use either their in-ear speakers, or revert back to using the original Autocom speakers.
Both of the above options work extremely well with in-ear speakers, it simply comes down to if the user wants to use in-ear speakers all the time, or if they might want to occasionally use either in-ear speakers or the original Autocom speakers.