Within days, Simpson was heading east again, taking a flying boat to Batavia, where he joined the advance party of the I Corps, which was being sent from the Middle East to the Dutch East Indies to counter the Japanese threat.
He met there with the local authorities regarding signals arrangements for the defence of Java.
These were soon well in hand, but the tactical situation rapidly deteriorated to the extent that the I Corps was ordered to leave Java on 21 February 1942.
Simpson departed on the troop ship Orcades, which arrived in Adelaide on 14 March.

Blamey was appointed Commander in Chief of the Australian Military Forces on 27 March.
He instituted a sweeping reorganisation of the Army, replacing officers with men who had experience in the Middle East.
Simpson became the Signal Officer in Chief on 6 April, with the rank of major general, the first Australian Corps of Signals officer to reach that rank.

One of Simpson's first tasks was to confer with the Chief Signals Officer at General Douglas MacArthur's General Headquarters (GHQ) South West Pacific Area, Brigadier General Spencer B. Akin.
The two established mechanisms to divide responsibility for the theatre's communications between the two armies, which often worked together on the same projects.
An important outcome of their first meeting was the creation of the Central Bureau as a combined signals intelligence organisation.
Simpson had been thinking about such an organisation while on the Orcades.
Blamey had an appreciation of signals intelligence from his time as Deputy Commander in Chief in the Middle East, and readily gave his support.
After a slow start, signals intelligence became an important element of the war in the South West Pacific.

Perhaps Simpson's most ambitious project was the laying of a submarine cable between Cape York and New Guinea.
A cable laying ship, the SS Mernoo, was chartered, and two old cables that ran across the Bass Strait were lifted and re-laid across the Torres Strait in October 1943.
When the land connections were completed in December 1943, it became possible to send a message all the way from Melbourne to Port Moresby.
Simpson, who was on an inspection tour of New Guinea, was on hand for the receipt of the first message.
In November 1944, he visited the front in the Netherlands, Belgium and France, returning to Australia via the United States and Canada.

To man his signals units, Simpson sought to obtain some 4,000 Australian Women's Army Service (AWAS) personnel.
Two special signal training battalions were activated to cater for them, and Simpson inspected the 2nd Signal Training Battalion (AWAS) at Ivanhoe Grammar School with Lieutenant Colonel Sybil Irving on 6 July 1942.
By 1945, the Australian Corps of Signals numbered some 25,000 men and women.
The large numbers of women serving in Signals units caused friction between Irving and Simpson over what degree of control he exercised over them.

Aware that signals is usually forgotten when the signallers are doing their best work, Simpson attempted to obtain various accolades for his corps.
He held ceremonial parades through Melbourne to celebrate VE Day on 10 May 1945, and VP Day on 20 August 1945.
He attempted to get the title "Royal" granted in recognition of its wartime service.
This occurred on 10 November 1948.
Within days, Simpson was heading east again, taking a flying boat to Batavia, where he joined the advance party of the I Corps, which was being sent from the Middle East to the Dutch East Indies to counter the Japanese threat. He met there with the local authorities regarding signals arrangements for the defence of Java. These were soon well in hand, but the tactical situation rapidly deteriorated to the extent that the I Corps was ordered to leave Java on 21 February 1942. Simpson departed on the troop ship Orcades, which arrived in Adelaide on 14 March.
Blamey was appointed Commander in Chief of the Australian Military Forces on 27 March. He instituted a sweeping reorganisation of the Army, replacing officers with men who had experience in the Middle East. Simpson became the Signal Officer in Chief on 6 April, with the rank of major general, the first Australian Corps of Signals officer to reach that rank.
One of Simpson's first tasks was to confer with the Chief Signals Officer at General Douglas MacArthur's General Headquarters (GHQ) South West Pacific Area, Brigadier General Spencer B. Akin. The two established mechanisms to divide responsibility for the theatre's communications between the two armies, which often worked together on the same projects. An important outcome of their first meeting was the creation of the Central Bureau as a combined signals intelligence organisation. Simpson had been thinking about such an organisation while on the Orcades. Blamey had an appreciation of signals intelligence from his time as Deputy Commander in Chief in the Middle East, and readily gave his support. After a slow start, signals intelligence became an important element of the war in the South West Pacific.
Perhaps Simpson's most ambitious project was the laying of a submarine cable between Cape York and New Guinea. A cable laying ship, the SS Mernoo, was chartered, and two old cables that ran across the Bass Strait were lifted and re-laid across the Torres Strait in October 1943. When the land connections were completed in December 1943, it became possible to send a message all the way from Melbourne to Port Moresby. Simpson, who was on an inspection tour of New Guinea, was on hand for the receipt of the first message. In November 1944, he visited the front in the Netherlands, Belgium and France, returning to Australia via the United States and Canada.
To man his signals units, Simpson sought to obtain some 4,000 Australian Women's Army Service (AWAS) personnel. Two special signal training battalions were activated to cater for them, and Simpson inspected the 2nd Signal Training Battalion (AWAS) at Ivanhoe Grammar School with Lieutenant Colonel Sybil Irving on 6 July 1942. By 1945, the Australian Corps of Signals numbered some 25,000 men and women. The large numbers of women serving in Signals units caused friction between Irving and Simpson over what degree of control he exercised over them.
Aware that signals is usually forgotten when the signallers are doing their best work, Simpson attempted to obtain various accolades for his corps. He held ceremonial parades through Melbourne to celebrate VE Day on 10 May 1945, and VP Day on 20 August 1945. He attempted to get the title "Royal" granted in recognition of its wartime service. This occurred on 10 November 1948.
Colin Hall Simpson