Question about Gigaset R700H Pro

Yes it should be compatible, it should because I haven't tried them. I haven't had a chance yet.
This info I am writing here is based on my technical understanding and research.
The R700H PRO is;
(1.) Gigaset DECT systems are equipped with Bluetooth® 4.2, or the integrated 3.5mm jack, and
(2.) In addition, the R700H PRO can also be connected to CAT-IQ 2.01 & GAP compatible base stations
in single and multi-cell environments from third-party providers.

DX800A (Pro) All In One should be the all in one telephone system. The most flexible telephone system.
According to the operating instructions:
Interfaces: ISDN, analogue landline, Ethernet, Bluetooth
(it really has everything old and new of the last 30 years & still future-proof. Super!)
DECT standard: is supported / GAP standard: is supported / Quality of Service: TOS, DiffServ
Protocols: DECT, GAP, SIP, RTP, DHCP, NAT Traversal (STUN), HTTP
(Here, too, everything is old and new from the last 30 years & still future-proof. Super!)

For me, this system has a nuance of weakness and has no ageing.
The only question here is how long the hardware and updating of the firmware and app will last (= software).

Conclusion to my knowledge; I would have liked a larger display.

The successor to the Gigaset DX800A (Pro) is the Gigaset Fusion FX800W PRO
Fusion is available in a bundle with two SL800H PRO handsets in the colour Dark Titanium.

The Gigaset Fusion FX800W PRO bundle will be available from the beginning of 2023 for around CHF 539 incl. VAT (RRP).
It really can do more than the Gigaset DX800A (Pro)
For all SMEs with up to 10 employees Definitely the best price-performance Made in Germany.
Gigaset Fusion FX800W PRO for approx. CHF 449.- would be a good price and with 2x even for approx. CHF 419.-
and trust me better than Fritz System.

The Gigaset Fusion FX800W PRO bundle looks more elegant, I miss some chrome,
in addition a larger display Spendiert which is movable up and down rotatable, u. Tiltable is, u.
with extension controllable with tablet and an external monitor.

I have a gigaset S850H and it also works with the

Yep, that's exactly how I have it with the DX800A Greetings